Ophthalmic Lens Molds, Ophthalmic Lenses Molded Therein, And Related Methods

ABSTRACT

Methods of manufacturing contact lenses using ophthalmic lens molds having a molding surface comprising a thermoplastic polymer, the molding surface having a percent polarity from 3% to 20% and a surface energy from about 25 mN/m to about 40 mN/m to cast mold a polymerizable composition having a surface tension from about 20 mN/m to about 25 mN/m, wherein a surface energy differential of the surface tension of the polymerizable composition less the surface energy of the molding surface less than or equal to zero (0); and silicone hydrogel contact lens bodies so manufactured are described.

FIELD

This application claims the benefit under 35 U.S.C. §119(e) of priorU.S. Provisional Patent Application No. 61/369,111, filed Jul. 30, 2010,which is incorporated in its entirety by reference herein.

The present disclosure relates to ophthalmic lens molds, ophthalmiclenses cast molded using these polar molds, and related methods.

BACKGROUND

In cast molding methods of producing ophthalmic lenses, such as contactlenses, a reaction mixture or polymerizable lens precursor compositionis cured in a lens shaped cavity defined by a first mold member with aconcave lens forming surface and a second mold member with a convex lensforming surface, or a female and male mold member, respectively. Themold members are typically produced by injection molding a thermoplasticpolymer into mold shaped cavities. Examples of thermoplastic polymersused to make ophthalmic lens molds include non-polar thermoplasticpolymers, such as polypropylene, polystyrene, and polyethylene; andpolar thermoplastic polymers, such as ethylene-vinyl alcohol polymersand polyvinyl alcohol polymers. When cast molding a contact lens, afterplacing the polymerizable composition in the first mold member, thefirst and second mold members are placed together or coupled together toform a lens assembly with the lens shaped cavity therebetween. The moldassembly is then cured to polymerize the polymerizable composition,forming the polymerized lens body in the lens shaped cavity of the moldassembly.

Over the years, a number of different types of thermoplastic polymermaterials, including polar and non-polar thermoplastic polymers, havebeen used to manufacture ophthalmic lenses using various types ofpolymerizable compositions and using various lens-making processes,including spin casting, lathing and cast molding.

When contact lens molds made of non-polar thermoplastic polymers such aspolypropylene or polystyrene are used to cast mold silicone hydrogelcontact lenses, it is known that additional measures typically need tobe taken in order to make the lens surfaces ophthalmically acceptablywettable. For example, a surface treatment such as a plasma treatmentcan be applied to the lens surfaces as part of the manufacturingprocess. Alternatively, a polymeric interpenetrating network wettingagent can be incorporated into the lens body as part of themanufacturing process in order to make the lens body ophthalmicallyacceptably wettable.

Recently, cast molding silicone hydrogel contact lenses in molds made ofhighly polar thermoplastic polymers such as ethylene-vinyl alcohol(EVOH) copolymers, for example SOARLITE™ S (a polar resin of EVOHcopolymers with an percent polarity of from about 10% to about 12%available from Nippon Gohsei, Ltd., Osaka, Japan) has been found toresult in lenses having ophthalmically acceptably wettable surfaces.Previously, when molded using non-polar thermoplastic polymers, it wasnecessary to apply a surface treatment such as, for example a plasmatreatment, or to include an interpenetrating network of a polymericwetting agent in silicone hydrogel contact lenses in order for the lenssurfaces to be ophthalmically acceptably wettable when hydrated. The useof contact lens molds comprising these highly polar thermoplasticpolymers (i.e., thermoplastic polymers with average polarities greaterthan or equal to 9%, such as, for example, greater than or equal to 10%,greater than or equal to 12%, greater than or equal to 15%, etc.) madeit possible to produce wettable silicone hydrogel contact lenses withoutthe need for a surface treatment, or an interpenetrating network of apolymeric wetting agent in the lens body. However, these highly polarthermoplastic polymers such as EVOH are expensive materials, whichnegatively impacts production costs. Molds made of EVOH typically areharder and more brittle than would be ideal, which negatively impactslens yields. Also, due to the high level of adhesion typically seenbetween EVOH molds and silicone hydrogels, after curing a siliconehydrogel contact lens body in a mold assembly of mold members comprisingEVOH, separation of the mold assembly to separate the two mold membersof the mold assembly typically requires a “wet” demolding process, i.e.,a demolding process involving the application of a liquid to the moldassembly containing the polymerized lens body, in order to allow the twomold members to be separated, leaving the lens body remaining in contactwith one and only one of the two mold members. It is believed that thehigh level of adhesion observed between EVOH molds and siliconehydrogels is due at least in part to the fact that EVOH is anelastomeric thermoplastic. Further, after wet demolding, the siliconehydrogel lens body may need to be exposed to an additional amount of aliquid during a “wet” delensing process in order to release the lensbody from the one remaining EVOH mold member with which it remained incontact following the demolding step. Additionally, silicone hydrogelcontact lenses often require the use of an organic solvent-based washingprocess in order for the lenses to become ophthalmically acceptablywettable, further increasing material, equipment and production costs.

US Patent Publication No. 2008/0290534 describes the desirability ofusing a mold having a surface energy less than 30 mN/m when the lensbody is released from the mold during aqueous hydration (i.e., when thelens is wet delensed), and teaches that using a monomer or cured lenshaving a surface energy which is greater than the surface energy of themold (such that the surface energy differential of the surface energy ofthe monomer or cured lens—the surface energy of the mold part is greaterthan 0) is preferred. This application discloses contact lens moldscomprising a thermoplastic polymer alone or a mixture of a thermoplasticpolymer and an additive, wherein the molds have a percent polarity from0% to 1.9% and a total surface energy less from 28 mN/m to 43 mN/m.

In view of the above, it can be appreciated that a need exists for newcontact lens molds having polar molding surfaces which can be used forcast molding silicone hydrogel ophthalmic lenses, particularly whenusing polymerizable compositions having relatively low surface tensions(e.g., a surface tension that is lower than the surface energy of themolding surface), new silicone hydrogel ophthalmic lenses cast moldedusing these molds and polymerizable compositions, and associatedmanufacturing methods that use less expensive, more process-friendlymolding materials, particularly molds which can be used to dry demoldand dry delens cast molded silicone hydrogel lens bodies formed fromthese polymerizable compositions, or which can produce silicone hydrogellens bodies having ophthalmically acceptably wettable surfaces fromthese polymerizable compositions without application of a surfacetreatment to the lens body or the presence of an interpenetratingnetwork (IPN) of a polymeric wetting agent in the polymerizablecomposition or lens body.

All publications, including patents, published patent applications,scientific or trade publications and the like, cited in thisspecification are hereby incorporated herein in their entirety.

SUMMARY

The present disclosure is directed to a method of manufacturing anophthalmic lens. In one example, the method is a method of manufacturinga silicone hydrogel contact lens body, the method comprising providing afirst mold member and a second mold member, the first mold membercomprising a concave molding surface configured to mold an anteriorsurface of a contact lens and the second mold member comprising a convexmolding surface configured to mold a posterior surface of a contactlens, the first mold member and the second mold member being configuredto form a lens-shaped cavity therebetween when combined as a moldassembly, the molding surface of at least one of the first mold memberand the second mold member comprising a thermoplastic polymer, themolding surface having a percent polarity from 3% to 20% and a totalsurface energy from about 25 mN/m to about 40 mN/m; placing apolymerizable composition comprising a) at least one silicon-containingmonomer and b) at least one hydrophilic monomer in the first moldmember, the polymerizable composition having a surface tension fromabout 20 mN/m to about 25 mN/m, and a surface energy differential of thesurface tension of the polymerizable composition less the surface energyof the molding surface is less than or equal to zero (0); assembling themold assembly by placing the second mold member in contact with thefirst mold member so as to form a lens-shaped cavity therebetween withthe polymerizable composition contained in the lens-shaped cavity of themold assembly; and curing the polymerizable composition in the moldassembly to form a cast-molded polymerized reaction product in thelens-shaped cavity of the mold assembly, the polymerized reactionproduct comprising a silicone hydrogel contact lens body.

The present disclosure is also directed to a silicone hydrogel contactlens body, the lens body comprising a cast-molded polymerized lens bodycomprising the reaction product of a polymerizable composition, thepolymerizable composition comprising a) at least one silicon-containingmonomer, and b) at least one hydrophilic monomer, the polymerizablecomposition having a surface tension from about 20 mN/m to about 25mN/m; wherein the lens body is cast-molded in a mold assembly comprisinga first mold member and a second mold member, at least one of the firstmold member and the second mold member having a thermoplastic polymermolding surface having a surface energy from about 25 mN/m to about 40mN/m and a surface energy differential between the surface tension ofthe polymerizable composition and the surface energy of the moldingsurface is less than or equal to zero (0); and the lens body hasophthalmically acceptably wettable anterior and posterior surfaceswithout application of a surface treatment to the lens body, or withoutthe presence of an interpenetrating network (IPN) of a polymeric wettingagent in the lens body.

The surface energy of the molding surface of at least one of the firstmold member and the second mold member can be from about 26 mN/m toabout 35 mN/m, or from about 27 mN/m to about 33 mN/m, or greater than30 mN/m.

The surface tension of the polymerizable composition can be from about21 mN/m to about 27 mN/m, or from about 22 mN/m to about 25 mN/m, orless than 25 mN/m.

In one example, the surface energy of the molding surface can be greaterthan 30 mN/m, and the surface tension of the polymerizable compositioncan be less than 25 mN/m. In another example, the surface energy of themolding surface can be from about 26 mN/m to about 33 mN/m, and thesurface tension of the polymerizable composition can be from about 21mN/m to about 25 mN/m.

In one example, the surface energy differential of the surface tensionof the polymerizable composition less the surface energy of the moldingsurface can be ≦−3, or can be ≦−5, or can be ≦−7, or can be ≦−9.

The thermoplastic polymer can comprise polypropylene.

The thermoplastic polymer can comprise a cyclic olefin homopolymer or acyclic olefin copolymer.

The thermoplastic polymer can comprise, consist essentially of, orconsist of polybutylene terephthalate (PBT).

The at least one of the first mold member and the second mold membercomprising the thermoplastic polymer molding surface can be formed byinjection molding. In one example, the mold tool used to form the moldmember can be maintained at a temperature from about 30° C. to about 70°C. during the injection molding.

In one example, the molding surface of the at least one of the firstmold member and the second mold member can comprise a mixture of athermoplastic polymer and an additive.

The molding surface formed of the mixture of the thermoplastic polymerand the additive can have a percent polarity at least 3 percentagepoints, or at least 5 percentage points, or at least 7 percentage pointshigher and a surface energy at least lmN/m lower, or at least 2 mN/mlower, or at least 3 mN/m lower than a molding surface formed under thesame conditions but of the thermoplastic polymer alone.

When present, the additive of the thermoplastic polymer of the moldingsurface can comprise a non-ionic surfactant, a fatty acid amide, or aform of silicone oil, or any combination thereof.

The additive can comprise, consist essentially of, or consist of a fattyacid amide. The fatty acid amide can comprise a primary amide, or asecondary amide, or a secondary bis-amide, or any combination thereof.

The additive can comprise a non-ionic surfactant. The non-ionicsurfactant can be a non-ionic surfactant having a structure including alinear hydrocarbon portion at least 8 carbons in length. The non-ionicsurfactant can comprise, consist essentially of, or consist of sorbitanoleate, or polyoxyethylene (80) sorbitan monooleate, or any combinationthereof

The percent polarity of the molding surface can be from 3% to 17%, orfrom 3% to 15%, or from 5% to 12%, or from 3% to 7%.

In one example, a percent polarity of a molding surface of the firstmold member and a percent polarity of a molding surface of the secondmold member can be the same.

The percent polarity of the polymerizable composition can be from about2% to about 10%, or from about 3% to about 9%, or from about 5% to about8%.

The polarity differential of a polarity of the polymerizable compositionless a polarity of the molding surface is from about +6 to about −6, orfrom about +4 to about −4, or from about +2 to about −2.

The spreading coefficient of the molding surface and the polymerizablecomposition can be greater than or equal to about 10 mN/m, or greaterthan or equal to about 13 mN/m.

The method can further comprise the steps of separating the moldassembly using a dry demolding method which does not involve applicationof a liquid to the mold assembly comprising the lens body, and ofdelensing the lens body using a dry delensing method which does notinvolve application of a liquid to the lens body.

The hydrophilic monomer of the polymerizable composition can comprise,consist essentially of, or consist of a hydrophilic monomer with anN-vinyl group. The hydrophilic monomer can comprise, consist essentiallyof, or consists of a hydrophilic amide monomer with an N-vinyl group.

The at least one silicon-containing monomer of the polymerizablecomposition can comprise, consist essentially of, or consist of asilicon-containing monomer having a first reactivity ratio, and the b)at least one hydrophilic monomer can comprise a hydrophilic monomerhaving a second reactivity ration, and the second reactivity ratio isless than the first reactivity ratio. The second reactivity ratio can beat least 5% less, or at least 10% less than the first reactivity ratio.

The average adhesion energy between the molding surface and thepolymerized lens body can be from about 45 mJ/m² to about 60 mJ/m², orfrom about 50 mJ/m² to about 55 mJ/m².

When fully hydrated, the lenses can have a contact angle of less than orequal to about 120°, less than or equal to about 90°, less than or equalto about 80°, less than or equal to about 60°, less than or equal toabout 50°, less than or equal to about 40°, less than or equal to about30°, or from about 10° to about 30°. In one example, the contact anglecan be measured using the sessile drop method.

Any and all of the preceding or following aspects/embodiments/featuresdescribed herein and combinations of such aspects/embodiments/featuresset forth in claims, sentences or paragraphs are included within thescope of the present application provided that theaspects/embodiments/features of any such combination in any such orderare not mutually inconsistent. In addition, anyaspect/embodiment/feature or combination of aspects/embodiments/featuresmay be specifically excluded from any example of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart illustrating steps of a method for producing anophthalmic lens.

FIG. 2 is a flow chart illustrating certain inputs and outputs of themethod of FIG. 1, including a polymerizable composition, a polymerizedlens body which has not been contacted by a liquid, a hydrated lensbody, and a packaged ophthalmic lens.

DETAILED DESCRIPTION

As used herein, “surface energy” is understood to refer to total surfaceenergy, and “surface tension” is understood to refer to total surfacetension. Total surface energy is the total of the disperse surfaceenergy and the polar surface energy of a solid. Similarly, total surfacetension is the total of the disperse surface tension and the polarsurface tension of a liquid.

The the total surface energy, the disperse disperse component surfaceenergy, and polar component of total surface energy, and the percentpolarity of a thermoplastic polymer can be determined using one or morestandard tests or assays which are conventional and well known in thepolymer art. One method is based on the Owens-Wendt-Rabel-Kaebel model,where the contact angle of the thermoplastic polymer is determined usinga number of different liquids of known polarities. TheOwens-Wendt-Rabel-Kaebel equation can be written in the form of a linearequation, where y is calculated based on the observed contact angle ofeach of the different liquids with the polymer (θ) and x is calculatedbased on the known polar (σ_(L) ^(P)) and disperse (σ_(L) ^(D))components of the total surface energy (σ_(L) ^(T)) of each of thedifferent liquids. The data points from the different liquids (x,y) canbe plotted, and the linear regression of the plot can then be used todetermine the slope (m) and y-intercept (b). The calculated slope andy-intercept can then be used to calculate the polar (σ_(S) ^(P)) anddisperse (σ_(s) ^(D)) components of the total surface energy of thepolar thermoplastic polymer (σ_(S) ^(T), where σ_(S) ^(T)=σ_(S)^(P)+σ_(S) ^(D)).

The Owens-Wendt-Rabel-Kaebel Equation in the form of a linear equation:

$\frac{\sigma_{L}( {{\cos \; \theta} + 1} )}{2\sqrt{\sigma_{L}^{D}}} = {\frac{\sqrt{\sigma_{S}^{P}}\sqrt{\sigma_{L}^{P}}}{\sqrt{\sigma_{L}^{D}}} + {\sqrt{\sigma_{S}^{D}}\mspace{14mu} {where}}}$${y = \frac{\sigma_{L}( {{\cos \; \theta} + 1} )}{2\sqrt{\sigma_{L}^{D}}}},{m = \sqrt{\sigma_{S}^{P}}},{x = \frac{\sqrt{\sigma_{L}^{P}}}{\sqrt{\sigma_{L}^{D}}}},{{{and}\mspace{14mu} b} = {\sqrt{\sigma_{S}^{D}}.}}$

Examples of the liquids with different polarities which can be used todetermine percent polarity of the thermoplastic polymer include, but arenot limited to, deionized water, diiodomethane, dimethyl sulfoxide(DMSO), and formamide. In selecting the liquids with differentpolarities, ideally, a number of liquids having a range of polaritiesbased on the liquid's polar component (σ_(L) ^(P)) of total surfaceenergy would be selected, rather than selecting a number of liquids withdifferent total surface energies (σ_(L) ^(T)). Using this method, thepercent polarity of the thermoplastic polymer is calculated by dividingthe calculated polar component (σ_(S) ^(P)) of total surface energy forthe polymer by its calculated total surface energy (as) and multiplyingby 100.

The thermoplastic polymer used in the devices and methods describedherein can have an average total surface energy of less than or equal toabout 32 mN/m, or from about 32 mN/m to about 50 mN/m, or from about 32mN/m to 42 mN/m, or from about 25 mN/m to about 40 mN/m, or from about26 mN/m to about 35 mN/m, or from about 27 mN/m to about 33 mN/m,orgreater than 30 mN/m.

The percent polarity of the molding surface can be from 2% to 20%, orfrom 3% to about 15%, or from 5% to 12%, or from 3% to 7%.

The surface energy and percent polarity can be determined using one ormore standard tests or assays which are conventional and well known inthe polymer art, including by the procedure based on theOwens-Wendt-Rabel-Kaebel model described above.

The surface tension and percent polarity of the polymerizablecomposition can be determined using one or more standard tests or assayswhich are conventional and well known in the polymer art. For example,the surface tension of the polymerizable composition can be calculatedusing the pendant drop method. The polar component of surface tension ofthe polymerizable composition can then be calculated using (a) the totalsurface tension (σ_(L) ^(T)) of the polymerizable composition asdetermine by the pendant drop method, and (b) a calculation of thedisperse component (σ_(L) ^(D)) of the total surface tension of thepolymerizable composition by determining the contact angle (θ) of thepolymerizable composition on Teflon (polytetrafluoroethylene, PTFE) byusing the equation:

$\sigma_{L}^{D} = {\frac{( \sigma_{L}^{T} )^{2}( {{\cos \; \theta_{PTFE}} + 1} )^{2}}{72}.}$

The measured disperse component of the surface tension (σ_(L) ^(D)) canthen be subtracted from the measured total surface tension (σ_(L) ^(T))to obtain the polar component of the surface tension using the equation:σ_(L) ^(P)=σ_(L) ^(T)−σ_(L) ^(D). The percent polarity of thepolymerizable composition is calculated by dividing the polar component(σ_(L) ^(P)) by the total surface energy (σ_(L) ^(T)) and multiplying by100.The surface tension of the polymerizable composition can be fromabout 20 mN/m to about 25 mN/m, or from from about 21 mN/m to about 27mN/m, or from about 22 mN/m to about 25 mN/m, or less than 25 mN/m.

The percent polarity of the polymerizable composition can be from about2% to about 10%, or from about 3% to about 9%, or from about 5% to about8%, or from about 1% to about 7%, or from about 2% to about 7%, or fromabout 3% to about 6%, or about 5%.

As at least one of the molding surfaces described herein has a surfaceenergy that differs from the surface tension of the polymerizablecomposition used to form the lens body, the surface energy differentialbetween the surface tension of the polymerizable composition and thesurface energy of the molding surface can be calculated by subtractingthe value of the surface energy of the molding surface from the value ofthe surface tension of the polymerizable composition. In other words,the surface energy differential, as used herein, is the value of thetotal surface tension of the polymerizable composition less the totalsurface energy of the thermoplastic molding surface. For the methods andlens bodies described herein, the value of the surface energydifferential is less than or equal to zero (0), e.g., the total surfaceenergy of the molding surface is greater than the total surface tensionof the polymerizable composition. For example, the surface energydifferential can be ≦−3, or can be ≦−5, or can be ≦−7, or can be ≦−9.

Similarly, a polarity differential can be calculated as well, bysubtracting the percent polarity of the molding surface from the percentpolarity of the polymerizable composition (i.e., the percent polarity ofthe polymerizable composition less the percent polarity of the moldingsurface). The polarity differential can be from about +6 to about −6, orfrom about +4 to about −4, or from about +2 to about −2.

The polarity differential of a polarity of the polymerizable compositionless a polarity of the molding surface is from about +6 to about −6, orfrom about +4 to about −4, or from about +2 to about −2.

. The spreading coefficient of the polymerizable composition and thethermoplastic polymer can be determined using one or more standard testsor assays which are conventional and well known in the polymer art. Forexample, the spreading coefficient can be determined based on thesurface energy of the mold member (σ_(S)), the surface energy of thepolymerizable composition (σ_(L)), and the interfacial tension at theinterface of the polymerizable composition and the mold member (σ_(sL))using the equation:

Spreading coefficient=σ_(S)−σ_(L)−σ_(SL).

In one example, when the polymerizable composition described herein isplaced in contact with a mold member comprising a thermoplastic polymeras described herein, the spreading coefficient of the polymeriziablecomposition and the mold member can be greater than or equal to about 10mN/m, or can be greater than or equal to about 13 mN/m, or can be fromabout 13 mN/m to about 18 mN/m, or from about 12 mN/m to about 15 mN/m.

The average adhesion energy of the mold assembly can be determined usingone or more standard tests or assays which are conventional and wellknown in the polymer art. For example, the average adhesion energy canbe calculated based on the disperse component of the total surfaceenergy of the polymerizable composition (σ_(L) ^(D)), the polarcomponent of the total surface energy of the polymerizable compositon(σ_(L) ^(P)), the disperse component of the total surface energy of thethermoplastic polymer (σ_(S) ^(P)), and the polar component of the totalsurface energy of the thermoplastic polymer (σ_(S) ^(P)). As previouslydescribed, the total surface energy, as well as the polar and dispersecomponents of the surface energy, can be calculated based on theOwens-Wendt-Rabel-Kaebel model. The adhesion energy of the mold assemblycan then be calculated using the equation:

Adhesion Energy=2[(σ_(S) ^(D)σ_(L) ^(D))^(1/2)(σ_(S) ^(P)σ_(L)^(P))^(1/2)].

In one example, when the polymerizable composition described herein iscured in a mold assembly comprising a thermoplastic polymer moldingsurface as described herein to form a polymerized lens body, the averageadhesion energy of the molding surface and the lens body can be greaterthan or equal to about 55 mJ/m2, or from about 55 mJ/m2 to about 63mJ/m2, or from about 58 mJ/m2 to about 61 mJ/m2, or from about 45 mJ/m2to about 60 mJ/m2, or from about 50 mJ/m2 to about 55 mJ/m2.

Examples of the thermoplastic polymers that may be employed inaccordance with the present disclosure include, without limitation,polyolefins, for example, polyethylene, polypropylene, polystyrene, andthe like and mixtures thereof. In one example, the thermoplastic polymercan comprise, consist essentially of, or consist of polypropylene. Inanother example, the thermoplastic polymer can comprise, consistessentially of, or consist of polybutylene terephthalate (PBT). Inanother example, the thermoplastic polymer can comprise, consistessentially of, or consist of a cyclic olefin polymer, including cyclicolefin homopolymers and cyclic olefin copolymers, and any combinationthereof. For example, the cyclic olefin polymer can comprise a form ofZEONOR™ polymer, such as, for example, ZEONOR 1420R™ (Zeon Chemicals,Louisville, Ky., USA).

In one example, the thermoplastic polymer of the present disclosure cancomprise, consist essentially of, or consist of a mixture of athermoplastic polymer and an additive.

The additive can be effective to alter the percent polarity and totalsurface energy of the thermoplastic polymer such that the mixture of theadditive and the thermoplastic polymer has a higher percent polarity anda lower total surface energy as compared to the thermoplastic polymerwithout the additive. For example, the percent polarity of the mixturecan be at least 1%, or at least 3%, or at least 5%, or at least 7%higher than the percent polarity of the thermoplastic without theadditive, while the total surface energy of the mixture can be at least1 mN/m, or at least 2 mN/m, or at least 4 mN/m lower than the totalsurface energy of the thermoplastic without the additive.

The additive can be selected from the group consisting of ionicsurfactants, fatty acid amides, silicone oil, and any combinationthereof.

The additive can comprise, consist essentially of, or consist of a fattyacid amide. The fatty acid amide can be a primary amide, a secondaryamide, a secondary bis-amide, or any combination thereof. In oneexample, the fatty acid amide can be a primary amide. The primary amidecan be CRODAMIDE OR™, or CRODAMIDE ER™ (Croda International Plc, Goole,East Yorkshire, UK).

The additive can comprise, consist essentially of, or consist of anon-ionic surfactant. The non-ionic surfactant can be a non-ionicsurfactant having a structure including a linear hydrocarbon portion atleast 8 carbons in length. The non-ionic surfactant can be sorbitanoleate, or polyoxyethylene (80) sorbitan monooleate, or any combinationthereof.

The additive can be present in the mixture in an amount from about 0.5%to about 20%, or from about 1% to about 10%, or from about 2% to about7%.

The additive can be present in the mixture in an amount effective toproduce a mixture having a polarity of from 3% to 20%, or of from 3% to15%, or of from 5% to 12%, or of from 3% to 7%.

In one example, both the molding surfaces of the first mold member andthe second mold member can be formed of the thermoplastic polymer orthermoplastic polymer mixture such that the molding surface of the firstmold member and the molding surface of the second mold member have thesame percent polarity, or the percent polarity of the two moldingsurfaces can differ by less than or equal to 10% or 5% of the value ofthe percent polarities.

In another example, the thermoplastic polymer can comprise a mixture ofa non-polar thermoplastic polymer and a polar thermoplastic polymer. Therelative amounts of the thermoplastic polymer(s) and non-polarpolymer(s) in the present molding surfaces may vary widely and depend onvarious factors, such as the specific thermoplastic polymer(s) employed,the specific non-polar polymer(s) employed, the specific lens materialto be employed, the specific lens (mold) design to be obtained and thelike factors. In one example, the non-polar polymer(s) comprise a minoramount, that is less than about 50%, by weight of the mixture of lesspolar polymer(s) and non-polar polymer(s). The non-polar polymer(s) maycomprise at least about 5%, about 10%, about 15%, about 20%, about 30%,or about 50% by weight of the mixture of less polar polymer(s) andnon-polar polymers(s). In another example, the non-polar polymer(s)comprise a major amount, that is greater than about 50%, by weight ofthe mixture of less polar polymer(s) and non-polar polymer(s). Thenon-polar polymer(s) may comprise at least about 50%, about 60%, about70%, about 80%, or about 90% by weight of the mixture of less polarpolymer(s) and non-polar polymers(s).

The combination of the non-polar polymer(s) and the polar polymer(s) canbe a combination of at least one non-polar polar polymer with at leastone polar polymer, wherein the at least one polar polymer has an percentpolarity greater than or equal to 9%, and the percent polarity of thecombination is from about 0.25% to about 8%, such as, for example, fromabout 1% to about 7%, from 2% to about 5%, from about 1% to about 4%, orof about 3%.

The combination of the non-polar polymer(s) and the polar polymer(s) canbe a combination of at least non-polar polar polymer with at least onepolar polymer, wherein the at least one polar polymer has an percentpolarity from about 0.25% to about 8%, and the percent polarity of thecombination is from about 0.25% to about 8%, such as, for example, fromabout 1% to about 7%, from 2% to about 5%, from about 1% to about 4%, orof about 3%.

In one example, the presence of the additive in admixture with thethermoplastic polymer can increase the percent polarity of the mixturewhile decreasing the total surface energy of the mixture as compared tothe thermoplastic polymer without the additive. For example, the moldingsurface formed of the mixture of the thermoplastic polymer and theadditive can have a percent polarity at least 3 percentage pointshigher, or at least 4 percentage points higher or at least 5 percentagepoints higher, or at least 7 percentage points higher and a surfaceenergy at least 1 mN/m, or at least 2 mN/m, or at least 3 mN/m lowerthan a molding surface formed under the same conditions but of thethermoplastic polymer alone.

As previously discussed, the thermoplastic polymer(s) used to form moldmembers, molding surfaces, or both, as described herein (i.e., thethermoplastic polymer(s), the non-polar thermoplastic polymer(s), thepolar thermoplastic polymer(s) and combinations thereof) can include oneor more additives. The additives can be present in the thermoplastic asa mixture. In one example, the additives can be effective in allowingcured silicone hydrogel contact lens bodies to be dry demolded, drydelensed, or both dry demolded and delensed from molding surfacescomprising the thermoplastic polymer and the additive. The additives canbe present in the thermoplastic as a mixture. In another example, theadditives can be effective in increasing the yield of cosmeticallyacceptable cured silicone hydrogel contact lens bodies when drydemolded, dry delensed, or both dry demolded and delensed from moldingsurfaces comprising the thermoplastic polymer and the additive, ascompared to the yield of cosmetically acceptable cured silicone hydrogelcontact lens bodies when dry demolded, dry delensed, or both drydemolded and delensed from molding surfaces that are substantiallyidentical but without the additive present. In yet another example, theadditives can be effective in reducing the rate of lens deformation ofcured silicone hydrogel contact lens bodies when dry demolded, drydelensed, or both dry demolded and delensed from molding surfacescomprising the thermoplastic polymer and the additive, as compared tothe rate of lens deformation of cured silicone hydrogel contact lensbodies when dry demolded, dry delensed, or both dry demolded anddelensed from molding surfaces that are substantially identical butwithout the additive present.

The present mold members can be produced by conventional injectionmolding procedures known to persons of ordinary skill in the art. Forexample, a quantity of the polymer material disclosed herein can beheated to form a molten thermoplastic polymer. The molten thermoplasticpolymer can be dispensed into a mold cavity in the shape of anophthalmic lens mold. For example, the mold cavity can include one ortwo optical quality molding surfaces. The optical quality moldingsurfaces can be provided as components of one or more removable insertslocated in a plate or other housing, or can be integrally machined aspart of the molding cavity. The molten thermoplastic polymer in the moldcavity can then be cooled and separated from the molding machine to bemoved to a station to receive a volume of the polymerizable composition.Alternatively, the present mold members can be produced by a combinationof injection molding and machining, lathing or ablating, for examplewhere the basic shape of the mold member is prepared by injectionmolding, and all or a portion of the optical quality molding surfacesare prepared by removing a portion of the mold member, for example bymachining, lathing or ablating a portion of the mold member, such as allor a part of the region of the mold used to mold an optical zone of acontact lens.

For injection molding the thermoplastic polymers described herein, inone example, the mold tool used to form the mold member can bemaintained at a temperature from about 30° C. to about 70° C. during theinjection molding process. Additionally or optionally, one or more ofthe following injection molding conditions can be used: melt temperaturefrom about 245° C. and about 270° C., holding temperature from about235° C. to about 270° C., feed temperature from about 235° C. to about250° C., holding pressure from about 60 bar to about 125 bar, andinjection speed from about 50 mm/sec. to about 125 mm/second through a 3mm aperture.

In one example, at least one of the molding surfaces used is effectiveto produce an ophthalmically acceptably wettable ophthalmic lens,including, but not limited to, an ophthalmically acceptably wettablesilicone hydrogel contact lens. The ophthalmically acceptably wettableophthalmic lens can also be an ophthalmically compatible lens, such as,for example, an ophthalmically compatible silicone hydrogel contactlens.

As used herein, an “ophthalmically compatible silicone hydrogel contactlens” refers to a silicone hydrogel contact lens that can be worn on aperson's eye without the person experiencing or reporting substantialdiscomfort, including ocular irritation and the like. Such lenses oftenhave an oxygen permeability, a surface wettability, a modulus, a watercontent, an ionoflux, a design, and combinations thereof, which permitthe lenses to be comfortably worn on a patient's eye for extendedperiods of time, such as for at least a day, at least a week, at leasttwo weeks, or about a month without requiring removal of the lens fromthe eye. Typically, ophthalmically compatible silicone hydrogel contactlenses do not cause or are not associated with significant cornealswelling, corneal dehydration (“dry eye”), superior-epithelial arcuatelesions (“SEALs”), or other significant discomfort. Ophthalmicallycompatible silicone hydrogel contact lenses meet clinical acceptabilityrequirements for daily wear or extended wear contact lenses.

Ophthalmically compatible silicone hydrogel contact lenses haveophthalmically acceptably wettable surfaces, although a lens withophthalmically acceptably wettable surfaces may not necessarily beophthalmically compatible. A silicone hydrogel contact lens having anophthalmically acceptably wettable surface can be understood to refer toa silicone hydrogel contact lens that does not adversely affect the tearfilm of a lens wearer's eye to a degree that results in the lens wearerexperiencing or reporting discomfort associated with placing or wearingthe silicone hydrogel contact lens on an eye.

Ophthalmic lenses comprise lens bodies that have surfaces, such as ananterior surface and a posterior surface. As used herein, anophthalmically acceptable wettable ophthalmic lens is a lens body withsurfaces that are all ophthalmically acceptably wettable. Wettabilityrefers to the hydrophilicity of one or more surfaces of a lens. As usedherein, a surface of a lens can be considered wettable, or to beophthalmically acceptably wettable, if the lens receives a score of 3 orabove in a wettability assay conducted as follows. An ophthalmic lens isdipped into distilled water, removed from the water, and the length oftime that it takes for the water film to recede from the lens surface isdetermined (e.g., water break up time (WBUT)). The assay grades lenseson a linear scale of 1−10, where a score of 10 refers to a lens in whicha drop takes 20 seconds or more to fall from the lens. A lens having aWBUT of more than 5 seconds, such as at least 10 seconds or moredesirably at least about 15 seconds, can be an ophthalmically acceptablywettable lens. Wettability can also be determined by measuring a contactangle on one or both lens surfaces. The contact angle can be a dynamicor static contact angle, a sessile drop contact angle, a pendant dropcontact angle, or a captive bubble contact angle. Lower contact anglesgenerally refer to increased wettability of a contact lens surface. Forexample, an ophthalmically acceptably wettable surface of a lens canhave a contact angle less than or equal to about 120 degrees when thelens is fully hydrated. However, in certain examples, the lenses have acontact angle no greater than about 90 degrees, and in further examples,the lenses have advancing contact angles less than or equal to about 80degrees, or less than or equal to about 60°, less than or equal to about50°, less than or equal to about 40°, less than or equal to about 30°,or from about 10° to about 30°. In one example, the contact angle can bemeasured using the sessile drop method.

As described herein, the ophthalmic lenses cast molded using thethermoplastic polymers have ophthalmically acceptably wettable surfaceswhen fully hydrated, and do not require application of a surfacetreatment or the presence of an interpenetrating network of a polymericwetting agent in the lens body in order for the lens to haveophthalmically acceptably wettable surfaces. However, application of asurface treatment to the lenses or the presence of an interpenetratingnetwork of a polymeric wetting agent in the lens body can be used tofurther increase the wettability of the lens surfaces above a level thatis considered ophthalmically acceptably wettable.

In contrast, the use of non-polar or hydrophobic polymers as theexclusive or predominant mold materials in mold members for cast moldingophthalmic lenses, including silicone hydrogel contact lenses, does notresult in the lens surfaces of the lens bodies so produced havingophthalmically acceptably wettable surfaces. Typically, ophthalmiclenses produced using non-polar or hydrophobic mold materials aresubjected to surface treatments after curing, or have aninterpenetrating network (IPN) of a polymeric wetting agent included inthe lens bodies, and as a result of the surface treatment or thepresence of the IPN, the lenses become ophthalmically acceptablywettable when fully hydrated. In other words, most silicone hydro gelcontact lens bodies that are cast molded in non-polar thermoplasticpolymer molds and which are not surface treated or do not include an IPNof a polymeric wetting agent are not ophthalmically acceptably wettablewhen fully hydrated.

As used herein, a “non-polar polymer contact lens mold” or “hydrophobicpolymer contact lens mold” refers to a contact lens mold having amolding surface that is formed or produced from a thermoplastic polymerhaving no polar component of total surface energy. For example, anon-polar polymer mold or a hydrophobic polymer mold may have a staticcontact angle of about 90° or more, as determined using the captivebubble method. With such contact angles, conventional ophthalmic lenses,including conventional silicone hydrogel contact lenses produced in suchmolds, do not have ophthalmically acceptably wettable surfaces. Further,the surfaces of such lenses typically do not have ophthalmicallyacceptably wettable surfaces.

One measure of the ability of a mold member, including a mold membercomprising a thermoplastic polymer, to mold as silicone hydrogel contactlens having ophthalmically acceptably wettable surfaces is the contactangle of the mold member. Contact angles can include dynamic or staticcontact angle, sessile drop contact angle, a pendant drop contact angle,or a captive bubble contact angle. In one example, the contact angle canbe measured using the captive bubble method, and can be performed inpurified water using a contact angle tester, such as Model CA-DTmanufactured by Kyowa Kaimen Kagaku Co., Ltd. or a Kruss DSA 100instrument (Kruss GmbH, Hamburg). The measurements can be performed at25° C.

The process of cast molding a silicone hydrogel contact lens bodytypically begins with the preparation of a pair of mold members (i.e., afirst mold member and a second mold member). The mold members can beproduced by injection molding a thermoplastic polymer mold material intomold shaped cavities, by lathing the polymer mold material to form theentire mold member, or by a combination of injection molding andlathing, for example, injection molding to form the basic shape of themold member and then lathing all or part of the lens forming region ofthe mold member.

Typically, two mold members are combined to cast mold contact lensbodies. The two mold members are sized and structured to be assembledtogether to define a lens-shaped cavity therebetween. Each of the twomold members can comprise either a concave lens forming surface used tomold an anterior surface of a lens, or a convex lens forming surfaceused to mold a posterior surface of a lens. For the purposes of thisdisclosure, the mold member with a concave lens forming surface isreferred to as a first mold member or a female mold member, and the moldmember with a convex lens forming surface is referred to as a secondmold member or a male mold member. The first and second mold members canbe structured to form a lens-shaped cavity therebetween when assembledwith each other to form a mold assembly. Alternative mold memberconfigurations, such as, for example, mold assemblies comprising morethan two mold members or mold members that are shaped or structureddifferently than described above, can be used with the low polaritythermoplastic polymer mold materials described herein. Additionally, themold members can be configured to comprise more than one lens formingregion. For example, a single mold member can be configured to comprisea region configured to mold an anterior lens surface as well as aposterior lens surface, i.e., to act as either a female or male moldmember.

At least one thermoplastic polymer can be used to form at least one moldmember, e.g., a first mold member or a second mold member, or can beused to form both mold members e.g., the first mold member and thesecond mold member.

As previously discussed, when the thermoplastic polymer materialsdescribed herein are used to make molding surfaces of mold membersconfigured to form a lens-shaped cavity therebetween as a mold assembly,the process of assembling the mold members into a mold assembly canfurther comprise the step of forming a connection of some sort betweenthe mold members. The first mold member and the second mold member canbe structured to be easily separated after being assembled together,preferably without causing substantial damage to at least one of thefirst and second mold members, and to an ophthalmic lens productproduced in the lens shaped cavity. In one example, the mold members canbe configured to form a mechanical connection based on the shape ofelements of the mold members, such as an interference fit between themold members, threading between the mold members, bores and protrusionsbetween the mold members, or other locking structures. In anotherexample, a weld can be formed between the mold members by melting aregion of one or more of the mold members. In yet another example, anadhesive substance such as a form of glue, contact cement or sealant canbe used to form a bond between the mold members. In yet another example,the mold members can be joined using an additional element such as aclip, clamp or bracket. Regardless of the type of connection usedbetween the mold members, the connection is intended to keep the moldmembers in alignment during the curing process, and needs to be capableof being released before the demolding process or as part of thedemolding process.

During the process of manufacturing a lens body, before the individualmold members are combined to form a mold assembly, the polymerizablelens forming composition is filled into the mold members. Typically thisis accomplished by placing a predetermined quantity of the polymerizablecomposition into the concave molding surface of the first mold member.The mold assembly is then assembled by placing the convex moldingsurface of the second mold member in contact with the first mold membersuch that a lens-shaped cavity is formed between the first and secondmold members, the lens-shaped cavity containing the polymerizablecomposition. If used, the connection is then formed between first andsecond mold members by whatever means is being used in order to maintainthe mold members in proper alignment during the curing process. Aspreviously described, the process of forming the connection cancomprise, for example, welding the mold members together, gluing themold members together, applying pressure to the mold members to engagean interference fit, threading the mold members together, applying aclamp to the mold members, etc.

The mold assembly including the polymerizable composition is then curedin the lens-shaped cavity to form a lens body. Curing typicallycomprises application of a form of electromagnetic radiation to the moldassembly including the polymerizable composition in order to causepolymerization of the polymerizable composition in the lens-shapedcavity of the mold assembly. The form of electromagnetic radiation cancomprise thermal radiation, visible light, ultraviolet (UV) light, etc.Combinations of two or more forms of electromagnetic radiation, as wellas two or more levels of one or more forms of electromagnetic radiation,can be used to cure the mold assemblies. The curing process typicallyinvolves curing the mold assembly until the polymerizable compositionhas polymerized sufficiently such that the lens body will retain theshape of the lens-shaped cavity following demolding and delensing. Assuch, the curing process may not result in complete reaction of all thepolymerizable components of the polymerizable composition.

Either “wet” or “dry” demolding methods can be used to separate the moldmembers of the mold assembly. As previously discussed, a wet demoldingmethod involves application of a liquid to a mold assembly including apolymerized lens body. When a wet demolding method is used, ultrasonicenergy can optionally be applied to the liquid and the mold assembly toassist with the demolding process.

Dry demolding processes involve the use of mechanical processes toseparate the two mold members of the mold assembly, the assemblyincluding the polymerized lens body. In dry demolding processes, themold assembly including the polymerized lens body is not contacted witha liquid, such as an organic solvent, water or an aqueous solutionduring the demolding process, and typically the mold assembly includingthe polymerized lens body has not been exposed to a liquid prior to thedry demolding process. Following a dry demolding process, thepolymerized lens body remains in contact with one, and only one, of thetwo mold members used to mold the lens body. In one example, a drydemolding process may include squeezing one or more of the mold membersto deform the mold member(s) and to separate the two mold members,leaving the polymerized lens body in contact with one of the two moldmembers. If the mold members of the mold assembly are held together atleast in part by an interference fit between the two mold members, a drydemolding process may include applying pressure to one or both of themold members in order to push the mold members away from each other tobreak the interference fit. If the mold members of the mold assembly areheld together at least in part by a weld between the two mold members,dry demolding may include cutting through the welded material.

It may be desired to have the lens body remain in contact with aparticular mold member, such as either the first or the second moldmember, following the demolding process. In order to help the lens bodyremain in contact with the desired mold member, heat can be applied tothe first or second mold member, for example, by blowing heated air onthe back of the mold member. Alternatively, the first or second moldmember can be chilled, for example by blowing chilled air on the back ofthe mold member. An application of pressure to either the first orsecond mold member before demolding or concurrently with the demoldingprocess can also help the lens body to remain in contact with aparticular mold member (i.e., the first or second mold member) followingthe demolding process.

Either “wet” or “dry” delensing methods can be used to separate the lensbody from the one and only one mold member (i.e., the first or secondmold member) with which it remains in contact following the demoldingstep. As previously discussed, a wet delensing method involvesapplication of a liquid to the polymerized lens body and the one andonly one mold member. When a wet delensing method is used, ultrasonicenergy can optionally be applied to the liquid and the one and only onemold member as part of the delensing process to assist in release of thelens body from the one and only one mold member. Following the wetdelensing, the released lens body can be immediately transferred to apackage or tray and inspected, or can optionally be allowed to sit inthe liquid used for the wet delensing (such as, for example, deionizedwater) for a period of time, for example to allow the released lens topartially or fully hydrate. The temperature of the delensing liquid canalso be controlled during the delensing process and optional sittingtime.

Dry delensing processes involve the use of mechanical processes torelease the lens body from the one remaining mold member with which thelens body is in contact following the demolding step. In dry delensingprocesses, the lens body and the one remaining mold member with whichthe lens body is in contact are not contacted by a liquid, such as wateror an aqueous solution, as part of the delensing process. While it ispossible that a wet demolding process (involving application of a liquidto a mold assembly including a polymerized lens body) may be used priorto a dry delensing process, it is more common to use a dry demoldingprocess prior to a dry delensing process. When a dry demolding processand a dry delensing process are used together, the lens body has notbeen exposed to a liquid, for example an organic solvent, water or anaqueous solution, until after the lens body has been released from bothmold members of the mold assembly (i.e., released from both the firstand second mold members). In one example, a dry delensing process mayinvolve the use of a vacuum apparatus to lift the polymerized lens bodyfrom the one remaining mold member with which it was in contactfollowing the demolding step. A dry delensing process may also involvesqueezing the one remaining mold member to at least partially break thebond between the one mold member. A dry delensing process may involveinserting a prying tool between the edge of the lens body and the moldmember to at least partially break the bond between the lens body andthe mold member.

The silicone hydrogel lens bodies cast molded using thermoplasticpolymer molds may not require the use of one or more organicsolvent-based washing steps in order for the resulting lens bodies to beophthalmically acceptably wettable, although organic solvent-basedwashing steps can be used to increase wettability or for other purposes.For example, these silicone hydrogel lens bodies are ophthalmicallyacceptably wettable following washing in aqueous solutions, includingaqueous solutions that are essentially free of an organic solvent suchas a volatile alcohol. Examples of volatile alcohols include forms ofmethanol, ethanol, propanol, etc. The aqueous solutions essentially freeof an organic solvent used to wash the present lenses can includeaqueous salt solutions, buffer solutions, surfactant solutions, wettingagent solutions, comfort agent solutions, combinations thereof, and thelike. In one example, one or more polymeric wetting agents or comfortagents can be used to wash the present lenses. However, it is understoodthat the present lenses have ophthalmically acceptably wettable surfaceswhen washed in an aqueous solution that does not contain any polymericwetting agents or comfort agents. Thus, while the polymeric wettingagents or comfort agents may be used to increase the wettability of thepresent lenses, their wettability is not dependent solely upon the useof such agents.

While the use of organic solvent-based washing steps is not necessary tothe make lenses described herein ophthalmically acceptably wettable, oneor more such steps can be used on the present lenses, for example, toclean the lens bodies by removing dust or debris; to extract the lensbodies by removing unreacted or partially reacted monomers, or othermaterials; or to partially hydrate the lenses (when an aqueous solutionof an organic solvent is used). Additionally, one or more organicsolvent-based washing steps can be performed on the present lens bodiesin order to increase the wettability of the lens bodies to a level abovethe ophthalmically acceptably wettable level achieved based on the useof the less polar mold materials in molding the lens bodies.

As used herein, the term “hydrogel” refers to a polymeric material,typically a network or matrix of polymer chains, capable of swelling inwater or becoming swollen with water. A hydrogel can also be understoodto be a material that retains water in an equilibrium state. The networkor matrix may or may not be cross-linked. Hydrogels refer to polymericmaterials, including contact lenses that are water swellable or arewater swelled. Thus, a hydrogel may be (i) unhydrated and waterswellable, or (ii) partially hydrated and swollen with water, or (iii)fully hydrated and swollen with water. The hydrogel may be a siliconehydrogel, a silicone-free hydrogel, or an essentially silicone-freehydrogel.

The term “silicone hydrogel” or “silicone hydrogel material” refers to aparticular hydrogel that includes a silicon (Si)-containing component ora silicone (SiO)-containing component. For example, a silicone hydrogelis typically prepared by combining a silicon-containing material withconventional hydrophilic hydrogel precursors. A silicone hydrogelcontact lens is a contact lens, including a vision correcting contactlens, which comprises a silicone hydrogel material.

A “silicon-containing” component is a component that contains at leastone silicon atom. The silicon-containing component can be a monomer. Inone example, one or more silicon atoms in the silicon-containingcomponent may optionally possess in some manner, for example, mayoptionally be chemically, such as covalently, bonded to, one or moreorganic radical substituents (R1, R2) or substituted organic radicalsubstituents. The organic radical substituents or substituted organicradical substituents may be the same or different, e.g., —SiR1R2O—.

“Molecular mass” in the context of a polymer described herein refers tothe nominal average molecular mass of a polymer, typically determined bysize exclusion chromatography, light scattering techniques, or intrinsicviscosity determination in 1,2,4-trichlorobenzene. Molecular weight inthe context of a polymer can be expressed as either a number-averagemolecular weight or a weight-average molecular weight, and in the caseof vendor-supplied materials, will depend upon the supplier. Typically,the basis of any such molecular weight determinations can be readilyprovided by the supplier if not provided in the packaging material.Typically, references herein to molecular weights of monomers orpolymers herein refer to the weight average molecular weight. Bothmolecular weight determinations, number-average and weight-average, canbe measured using gel permeation chromatographic or other liquidchromatographic techniques. Other methods for measuring molecular weightvalues can also be used, such as the use of end-group analysis or themeasurement of colligative properties (e.g., freezing-point depression,boiling-point elevation, or osmotic pressure) to determinenumber-average molecular weight or the use of light scatteringtechniques, ultracentrifugation or viscometry to determineweight-average molecular weight.

A “network” or “matrix” of a hydrophilic polymer typically means thatcrosslinks are formed between polymer chains by covalent bonds or byphysical bonds, e.g. hydrogen bonds. A network can include two or morepolymeric components, and can include an interpenetrating network (IPN)in which one polymer is physically entangled with a second polymer suchthat there are few, if any, covalent bonds between them, but thepolymers cannot be separated from each other without destroying thenetwork.

A “hydrophilic” substance is one that is water-loving or has an affinityfor water. Hydrophilic compounds have an affinity to water and areusually charged or have polar moieties or groups that attract water.

A “hydrophilic polymer” as used herein is defined as a polymer having anaffinity for water and capable of absorbing water. A hydrophilic polymeris not necessarily soluble in water. A hydrophilic polymer may besoluble in water or insoluble, e.g., substantially insoluble, in water.

A “hydrophilic component” is a hydrophilic substance that may or may notbe a polymer. Hydrophilic components include those that are capable ofproviding at least from about 20% (w/w), for example, at least fromabout 25% (w/w) water content to the resulting hydrated lens whencombined with the remaining reactive components. A hydrophilic componentcan include hydrophilic monomers, hydrophilic polymers, or combinationsthereof. Hydrophilic monomers may also be understood to have hydrophilicportions and hydrophobic portions. Typically, the hydrophilic portionand the hydrophobic portion are present in relative amounts such thatthe monomersor polymers are hydrophilic.

A monomer can be a relatively low molecular weight compound, for examplea compound with an average molecular weight less than or equal to about700 Daltons that is polymerizable. In one example, a monomer cancomprise a single unit of a molecule containing one or more functionalgroups capable of polymerizing to combine with other molecules to form apolymer, the other molecules being of the same structure or differentstructures as the monomer.

As used herein, “monomer” can also refer to medium and high molecularweight compounds or polymers, which can contain one or more functionalgroups capable of polymerization or further polymerization. For example,a monomer can be a compound or polymer with an average molecular weightof from about 700 Daltons to about 2,000 Daltons.

As used herein, “monomer” can also refer to a polymerizable orcrosslinkable higher molecular weight compound. A monomer as used hereincan contain one or more functional groups. In one example, a monomer canbe a series of monomers bonded together such that the overall moleculeremains polymerizable or crosslinkable. For example, a monomer can be acompound with an average molecular weight greater than or equal to about2,000 Daltons.

A “polymer” refers to a material formed by polymerizing one or moremonomers. As used herein, a polymer is understood to refer to a moleculethat is not capable of being polymerized, but is capable of beingcrosslinked to other polymers, for example, to other polymers present ina polymerizable composition or during the reaction of monomers to formother polymers in a polymerizable composition.

An “interpenetrating network” or “IPN” refers to a combination of two ormore different polymers, in network form, of which at least one issynthesized (e.g., polymerized) and/or cross-linked in the presence ofthe other without or substantially without any covalent bonds betweenthem. An IPN can be composed of two kinds of chains forming two separatenetworks, but in juxtaposition or interpenetrating. Examples of IPNsinclude sequential IPNs, simultaneous IPNs, semi-IPNs and homo-IPNs.

A “pseudo IPN” refers to a polymeric reaction product where at least oneof the different polymers is cross-linked while at least one otherpolymer is non-crosslinked (e.g. linear or branched), wherein thenon-cross-linked polymer is distributed in and held by the cross-linkedpolymer on a molecular scale such that the non-cross-linked polymer issubstantially unextractable from the network.

A “polymeric mixture” refers to a polymeric reaction product whereindifferent polymers are either linear or branched, substantially withoutcross-linking, wherein the resulting polymeric blend that is obtained isa polymer mixture on a molecular scale.

A “graft polymer” refers to a branched polymer having side chainscomprising a homopolymer or copolymer different to that of the mainchain.

“Attach” can refer to any of charge attachment, graft, complex, bond(chemical bond or hydrogen), or adhere, unless specified otherwise.

As used herein, an “ophthalmically acceptable lens forming component”refers to a lens forming component that can be incorporated into ahydrogel contact lens without the lens wearer experiencing or reportingsubstantial discomfort, including ocular irritation and the like.Ophthalmically acceptable hydrogel contact lenses have ophthalmicallyacceptable surface wettabilities, and typically do not cause or are notassociated with significant corneal swelling, corneal dehydration (“dryeye”), superior-epithelial arcuate lesions (“SEALs”), or othersignificant discomfort.

The term “organic solvent” refers to an organic substance which has theability to solvate or dissolve at least one material, for example andwithout limitation, unreacted materials, diluents and the like, presentin a contact lens body which has not previously been subjected toextraction processing. In one example, the material is a material thatis not soluble or does not dissolve in water or an aqueous solution. Inanother example, the material is a material that is not as soluble ordoes not dissolve as much in water or an aqueous solution, i.e., thematerial has increased solvation in the organic solvent as compared towater or an aqueous solution. Thus, the organic solvent in contact withsuch an unextracted contact lens body is effective to solvate ordissolve at least one material present in the lens body, or to increasethe solvation or dissolve to a greater extent the at least one materialpresent in the lens body to reduce the concentration of the at least onematerial in the lens body, or to reduce the concentration of the atleast one material in the lens body as compared to a lens body treatedwith water or an aqueous solution. The organic solvent may be usedwithout dilution, that is 100% organic solvent, or may be used in acomposition including less than 100% organic solvent, for example andwithout limitation, an aqueous solution including an organic solvent. Ingeneral, an organic solvent acts, for example, directly acts, on the atleast one material to solvate or dissolve the at least one material.Examples of organic solvents include, without limitation, alcohols,e.g., alkanols, such as ethanol, isopropanol and the like, chloroform,butyl acetate, tripropylene glycol methyl ether, dipropylene glycolmethyl ether acetate, and the like and mixtures thereof.

The term “surfactant” or “surfactant component” refers to a substancewhich has the ability to reduce the surface tension of water, forexample, water or an aqueous solution in which the substance is present.By reducing the surface tension of the water, the surfactant orsurfactant component facilitates the water containing the surfactant orsurfactant component, when in contact with a contact lens body which hasnot previously been subjected to extraction processing with an organicsolvent, to more intimately contact the lens body and/or moreeffectively wash or remove at least one material present in the lensbody from the lens body relative to the water without the surfactant orsurfactant component. Generally, a surfactant or surfactant componentdoes not act directly on the at least one material to solvate ordissolve the at least one material. Examples of surfactants orsurfactant components include, without limitation, zwitterionicsurfactants including forms of betaine, non-ionic surfactants includingforms of polysorbate such as polysorbate 80, forms of poloxamers orpoloxamines, fluorinated surfactants, and the like and mixtures thereof.In one example, one or more surfactants can be incorporated into thepolymerizable compositions described herein, in washing liquidsdescribed herein, in the packaging solutions described herein, andcombinations thereof.

Additional definitions may also be found in the sections that follow.

Lens formulations. Hydrogels represent one class of materials used forthe present contact lenses. Hydrogels comprise a hydrated, cross-linkedpolymeric system containing water in an equilibrium state. Accordingly,hydrogels are copolymers prepared from one or more reactive ingredients.The reactive ingredients are crosslinkable with a crosslinking agent.

Hydrophilic monomer. The hydrophilic monomer can be, for example, asilicon-containing monomer having a hydrophilic portion, a hydrophilicsilicon-free monomer, or a combination thereof. The hydrophilic monomercan be used in combination with a hydrophobic monomer. The hydrophilicmonomer can be a monomer having both hydrophilic and hydrophobicportions or moieties. The type and amount of hydrophilic monomer used inthe polymerizable lens composition can vary depending on the types ofother lens-forming monomers that are used. Non-limiting illustrationsare provided herein with respect to hydrophilic monomers for use insilicone hydrogels.

Crosslinking Agent. Crosslinking agents for the monomersused inpreparing the hydrogels can include those that are known in the art, andexamples of the crosslinking agents are also provided herein. Suitablecrosslinking agents include, for example, a diacrylate- (or divinylether-) functionalized ethylene oxide oligomer or monomer, such as, forexample, tri(ethylene glycol) dimethacrylate (TEGDMA) tri(ethyleneglycol) divinyl ether (TEGDVE), ethylene glycol dimethacrylate (EGDMA),and trimethylene glycol dimethacrylate (TMGDMA). Typically, thecrosslinking agents are present in the polymerizable silicone hydrogelcomposition in relatively small total amounts in the polymerizablecomposition, such as in an amount ranging from about 0.1% (w/w) to about10% (w/w), or from about 0.5% (w/w) to about 5% (w/w), or from about0.75% (w/w) to about 1.5% (w/w), by weight of the polymerizablecomposition.

In one example, one or more of the monomers may comprise crosslinkingfunctionality. In such cases, the use of an additional crosslinker inaddition to the monomer with crosslinking functionality is optional, andthe monomer with crosslinking functionality may be present in thepolymeriziable silicone hydrogel composition in a larger amount, suchas, for example, at least about 3% (w/w), at least about 5% (w/w), atleast about 10% (w/w), or at least about 20% (w/w).

Silicone Hydrogel Polymerizable Lens Forming Composition. A siliconehydrogel polymerizable lens forming composition can comprise at leastone silicon-containing component and at least one compatible hydrophilicmonomer. In one example, the polymerizable composition can be apolymerizable composition that is free of a polymeric wetting agent. Inanother example, the polymerizable composition can further comprise atleast one compatible crosslinking agent. In another example, thesilicon-containing component may act as both a crosslinker and as asilicon-containing component. With respect to polymerizable compositionsas discussed herein, “compatible” components refers to components which,when present in a polymerizable composition prior to polymerization,form a single phase that is stable for a duration of time adequate toallow manufacture of a polymerized lens body from the composition. Forsome components, a range of concentrations may be found to becompatible. Additionally, “compatible” components are components which,when polymerized to form a polymerized lens body, produce a lens thathas adequate physical characteristics to be used as a contact lens(e.g., adequate transparency, modulus, tensile strength, etc.)

Silicon-containing component. The Si and, when present, attached Oportion (Si—O portion) of the silicon-containing component can bepresent in the silicon-containing component in an amount greater than orequal to 20% (w/w), for example greater than or equal to 30% (w/w), ofthe total molecular weight of the silicon-containing component. Usefulsilicon-containing components comprise polymerizable functional groupssuch as vinyl, acrylate, methacrylate, acrylamide, methacrylamide,N-vinyl lactam, N-vinylamide, and styryl functional groups. Thesilicon-containing component from which the present contact lenses maybe obtained, for example, by polymerization, include one or moresilicon-containing monomers. Silicone hydrogel contact lenses producedas described herein can be based on a silicon-containing monomer, and ahydrophilic monomer or co-monomer, and a crosslinking agent. In additionto the other silicon-containing compounds described herein, examples ofstill further silicon-containing components that may be useful in thepresent lenses can be found in U.S. Pat. Nos. 3,808,178; 4,120,570;4,136,250; 4,139,513; 4,153,641; 4,740,533; 5,034,461; 5,496,871;5,959,117; 5,998,498; and 5,981,675, and U.S. Pat. ApplicationPublication Nos. 2007/0066706 A1, 2007/0296914 A1, and 2008/0048350 A1,all of which are incorporated in their entireties herein by reference. Asilicon-containing monomer can have, for example, the following generalstructure (I):

where R⁵ is H or CH₃, X is O or NR⁵⁵ where R⁵⁵ is H or a monovalentalkyl group with 1 to 4 carbon atoms, a is 0 or 1, L is a divalentlinking group which comprises from 1 to 20 carbon atoms, or from 2 to 10carbon atoms, which can also optionally comprise ether and/or hydroxylgroups, for example, a polyethylene glycol chain, p can be from 1 to 10,or from 2 to 5, R₁ R₂, and R₃ can be the same or different and aregroups independently selected from hydrocarbon groups having 1 to about12 carbon atoms (e.g., methyl groups), hydrocarbon groups substitutedwith one or more fluorine atoms, a siloxanyl group, and siloxanechain-containing moieties, wherein at least one of R₁, R₂, and R₃comprises at least one siloxane unit (—OSi). For example, at least ofone of R₁, R₂, and R₃ can comprise —OSi(CH₃)₃ and/or —OSi(R⁵²R⁵³R⁵⁴)where R⁵², R⁵³ R⁵⁴ are independently ethyl, methyl, benzyl, phenyl or amonovalent siloxane chain comprising from 1 to about 100, or from about1 to about 50, or from about 1 to about 20, repeating Si—O units.

One, two, or all three of R₁, R₂, and R₃ can also comprise othersiloxanyl groups or siloxane chain-containing moieties. The combinedlinkage of —X—L—,where present in a silicon-containing monomer ofstructure (I), can contain one or more heteroatoms that are either O orN. The combined linkage can be straight chain or branched, where carbonchain segments thereof can be straight chain. The combined linkage of—X—L— can optionally contain one or more functional groups selectedfrom, e.g., carboxyl, amide, carbamate, and carbonate. Examples of suchcombined linkages are provided, for example, in U.S. Pat. No. 5,998,498and U.S. Pat. Application Publication Nos. 2007/0066706 A1, 2007/0296914A1, and 2008/0048350, all the disclosures of which are incorporatedherein by reference. The silicon-containing monomer used in accordancewith the present disclosure can comprise a single unsaturated oracryloyl group, such as shown in structure (I), or optionally canpossess two unstaturated or acryloyl groups, such as one at eachterminus of the monomer, monomer or prepolymer. Combinations of bothtypes of the silicon-containing monomers optionally can be used inpolymerizable compositions useful in accordance with the presentdisclosure.

Examples of silicon-containing components useful in accordance with thepresent disclosure include, for example and without limitation,polysiloxanylalkyl (meth)acrylic monomers including, without limitation,methacryloxypropyl tris(trimethylsiloxy)silane, pentamethyldisiloxanylmethylmethacrylate, and methyldi(trimethylsiloxy)methacryloxymethylsilane.

Specific examples of the useful silicon-containing monomers can be, forexample, 3-[tris(trimethylsilyloxy)silyl]propyl methacrylate (“Tris”available from Gelest, Morrisville, Pa., USA), andmonomethacryloxypropyl terminated polydimethylsiloxane (“MCS-M11”available from Gelest, Morrisville, Pa., USA). Examples of somesilicon-containing monomers are disclosed in US Patent ApplicationPublication No. 2008/0269429. These silicon-containing monomers can havean alkylene group as a divalent linkage group (e.g., —(CH₂)_(p)—) and“a” can be 0 with reference to structure (I), and at least two siloxanylgroups. These silicon-containing components are designated herein asStructure (A) class silicon-containing monomers. Exemplary non-limitingstructures of these silicon-containing monomers are shown as follows:

Other specific examples of silicon-containing components useful in thepresent disclosure can be, for example,3-methacryloxy-2-hydroxypropyloxy)propylbis (trimethylsiloxy)methylsilane (“SiGMA”, available from Gelest, Morrisville, Pa., USA) andmethyldi(trimethylsiloxy)sylylpropylglycerolethyl methacrylate(“SiGEMA”). These silicon-containing components include at least onehydroxyl group and at least one ether group in the divalent linkinggroup L shown in structure (I) and at least two siloxanyl groups. Thesesilicon-containing components are designated herein as Structure (B)class silicon-containing components. Additional details on this class ofsilicon-containing components are provided, for example, in U.S. Pat.No. 4,139,513, which is incorporated in its entirety herein byreference. SiGMA, for example, can be represented by the followingexemplary non-limiting structure:

Silicon-containing components of Structures (A) and (B) can be usedindividually or in any combinations thereof in polymerizablecompositions useful in accordance with the present disclosure.Silicon-containing components of structures (A) and/or (B) may befurther used in combination with at least one silicon-free hydrophilicmonomer such as described herein. If used in combination, for example,the amount of silicon-containing components of Structure (A) can be, forexample, from about 10% (w/w) to about 40% (w/w), or from about 15%(w/w) to about 35% (w/w), or from about 18% (w/w) to about 30% (w/w).The amount of silicon-containing components of Structure (B) can be, forexample, from about 10% (w/w) to about 45% (w/w), or from about 15%(w/w) to about 40% (w/w), or from about 20% (w/w) to about 35% (w/w).

Other specific examples of the useful silicon-containing componentsuseful in accordance with the present disclosure can be chemicalsrepresented by the following formulas, or chemicals described inJapanese patent application publication number 2008-202060A, which ishereby incorporated by reference in its entirety, for example,

Yet other specific examples of the useful silicon-containing componentsuseful in accordance with the present disclosure can be chemicalsrepresented by the following formulas, or chemicals described in U.S.Patent Application Publication Number 2009/0234089, which is herebyincorporated by reference in its entirety. In one example, thesilicon-containing component can comprise one or more a hydrophilicpolysiloxane components represented by general formula (II),

wherein R₁ is selected from either hydrogen or a methyl group; R₂ isselected from either of hydrogen or a C₁₋₄ hydrocarbon group; mrepresents an integer of from 0 to 10; n represents an integer of from 4to 100; a and b represent integers of 1 or more; a+b is equal to 20-500;b/(a+b) is equal to 0.01−0.22; and the configuration of siloxane unitsincludes a random configuration. Examples of such silicon-containingcomponents are described in the Examples section of U.S. PatentApplication Publication Number 2009/0234089, including Example 2 on page7.

Other silicon-containing components also can be used. For example, othersuitable types can include, for example, poly(organosiloxane) monomerssuch as α,ω-bismethacryloxy-propyl polydimethylsiloxane. Another exampleis mPDMS (monomethacryloxypropyl terminated mono-n-butyl terminatedpolydimethylsiloxane). Other useful silicon-containing componentsinclude silicon-containing vinyl carbonate or vinyl carbamate monomersincluding, without limitation, 1,3 -bis[4-(vinyloxycarb-onyloxy)but-1-yl]tetramethylisiloxane 3-(vinyloxycarbonylthio)propyl-[tris(trimethylsiloxysilane], 3- [tris(trimethylsiloxy)silyl]propyl allylcarbamate, 3-[tris(trimethylsiloxy)silyl]propyl vinyl carbamate;trimethylsilylethyl vinyl carbonate, and trimethylsilylmethyl vinylcarbonate. Examples of one or more of these silicon-containingcomponents can be provided, for example, in U.S. Pat. No. 5,998,498 andU.S. Pat. Application Publication Nos. 2007/0066706 A1, 2007/0296914 A1,and 2008/0048350, all the disclosures of which are incorporated hereinby reference.

Some of the silicon-containing monomers that can be used in accordancewith the present disclosure can be used as a single discrete monomer, orcan be used as a mixture of two or more discrete monomers. For example,MCR-M07 is often provided as a mixture of silicon-containing compoundswith a wide distribution of molecular weights. Alternatively, some ofthe silicon-containing monomers that can be used in accordance with thepresent disclosure can be provided as two or more monomers with discretemolecular weights. For example, X-22-1625 is available in a lowermolecular weight version with a molecular weight of about 9000 Daltons,and as a higher molecular weight version with a molecular weight ofabout 18,000 Daltons.

The polymerizable compositions for use as described herein may includeone or more hydrophobic monomers, including silicon-free hydrophobicmonomers. Examples of such silicon-free hydrophobic monomers include,without limitation, acrylic and methacrylic acids and derivativesthereof, including methylmethacrylate, Combinations of two or morehydrophobic monomers may be employed.

Hydrophilic Monomers. Hydrophilic monomers, including silicon-freehydrophilic monomers, are included in the polymerizable compositionsused to make the present silicone hydrogels. The silicon-freehydrophilic monomers exclude hydrophilic compounds that contain one ormore silicon atoms. Hydrophilic monomers can be used in combination withsilicon-containing monomers in the polymerizable compositions to formsilicone hydrogels. In silicone hydrogels, hydrophilic monomercomponents include those that are capable of providing at least about10% (w/w), or even at least about 25% (w/w) water content to theresulting hydrated lens when combined with the other polymerizablecomposition components. For silicone hydrogels, the total hydrophilicmonomers can be from about 25% (w/w) to about 75% (w/w), or from about35% (w/w) to about 65% (w/w), or from about 40% (w/w) to about 60%(w/w), of the polymerizable composition.

Monomers that may be included as the hydrophilic monomers typicallypossess at least one polymerizable double bond, at least one hydrophilicfunctional group, or both. Examples of polymerizable double bondsinclude, for example, vinyl, acrylic, methacrylic, acrylamido,methacrylamido, fumaric, maleic, styryl, isopropenylphenyl,O-vinylcarbonate, O-vinylcarbamate, allylic, O-vinylacetyl and N-vinyllactam and N-vinylamido double bonds. In one example, the hydrophilicmonomers are vinyl-containing (e.g., an acrylic containing monomer or anon-acrylic vinyl containing monomer). Such hydrophilic monomers maythemselves be used as crosslinking agents.

Such hydrophilic monomers may be, but are not necessarily, crosslinkingagents. Considered as a subset of acryloyl moieties as described above,an “acrylic-type” or “acrylic-containing” or acrylate-containing monomeris a monomer containing the acrylic group (CR′H═CRCOX) wherein R is H orCH₃, R′ is H, alkyl, or carbonyl, and X is O or N, which are also knownto polymerize readily.

For silicone hydrogels, the hydrophilic component can comprisesilicon-free hydrophilic monomer components comprising an acrylicmonomer (e.g., a monomer with a vinyl group at the α-carbon position anda carboxylic acid terminus, a monomer with a vinyl group at the α-carbonposition and an amide terminus, etc.) and hydrophilic vinyl-containing(CH₂═CH—) monomer (i.e., a monomer containing a vinyl group that is notpart of an acrylic group).

Illustrative acrylic monomers include N,N-dimethylacrylamide (DMA),2-hydroxyethyl acrylate, glycerol methacrylate, 2-hydroxyethylmethacrylate (HEMA), methacrylic acid, acrylic acid, methylmethacrylate(MMA), ethylene glycol methyl ether methacrylate (EGMA), and anymixtures thereof. In one example, the total acrylic monomer content isin an amount ranging from about 5% (w/w) to about 50% (w/w) of thepolymerizable composition used to prepare a silicone hydrogel lensproduct, and can be present in an amount ranging from about 10% (w/w) toabout 40% (w/w), or from about 15% (w/w) to about 30% (w/w), of thepolymerizable composition.

As described above, the hydrophilic monomer also can comprise ahydrophilic vinyl-containing monomer. In one example, the hydrophilicmonomer of the present disclosure can comprise, consist essentially of,or consist of a hydrophilic monomer having an N-vinyl group. In anotherexample, the hydrophilic monomer of the present disclosure can comprise,consist essentially of, or consist of a hydrophilic amide monomer havingan N-vinyl group. Hydrophilic vinyl-containing monomers that may beincorporated into the materials of the present lenses include, withoutlimitation, the following: N-vinyl lactams (e.g. N-vinyl pyrrolidone(NVP)), N-vinyl-N-methyl acetamide (VMA), N-vinyl-N-ethyl acetamide,N-vinyl-N-ethyl formamide, N-vinyl formamide, N-2-hydroxyethyl vinylcarbamate, N-carboxy-β-alanine N-vinyl ester and the like and mixturesthereof. One example of a vinyl-containing monomer is N-vinyl-N-methylacetamide (VMA). The structure of VMA corresponds toCH₃C(O)N(CH₃)—CH═CH₂. In one example, the total vinyl-containing monomercontent of the polymerizable composition is in an amount ranging fromabout 0% to about 50% (w/w), e.g., up to about 50% (w/v), of thepolymerizable composition used to prepare the silicone hydrogel lensproduct, and can be present in an amount ranging from about 20% (w/w) toabout 45% (w/w), or from about 28% (w/w) to about 40% (w/w), of thepolymerizable composition. Other silicon-free lens-forming hydrophilicmonomers known in the art also may be suitable.

Additional examples are the hydrophilic vinyl carbonate or vinylcarbamate monomers disclosed in U.S. Pat. No. 5,070,215, and thehydrophilic oxazolone monomers disclosed in U.S. Pat. No. 4,190,277.Other suitable hydrophilic monomers will be apparent to one skilled inthe art. More preferred hydrophilic monomers which may be incorporatedinto the polymer of the present disclosure include hydrophilic monomerssuch as N,N-dimethyl acrylamide (DMA), 2-hydroxyethyl acrylate, glycerolmethacrylate, 2-hydroxyethyl methacrylamide, N-vinylpyrrolidone (NVP),and polyethyleneglycol monomethacrylate. In certain examples,hydrophilic monomers including DMA, NVP and mixtures thereof areemployed.

Additional examples of materials used to make silicone hydrogel contactlenses include those materials disclosed in U.S. Pat. No. 6,867,245.

Crosslinking agents useful in producing the present contact lenses, suchas the present silicone hydrogel contact lenses include, withoutlimitation, the above-indicated crosslinking agents. Examples ofacrylate-functionalized ethylene oxide oligomers for use in crosslinkingagents can include oligo-ethylene oxide dimethacrylate. The crosslinkingagent can be TEGDMA, TEGDVE, EGDMA, TMGDMA, or any combinations thereof.Typically, the crosslinking agents are present in the polymerizablesilicone hydrogel composition in relatively small total amounts in thepolymerizable composition, such as in an amount ranging from about 0.1%(w/w) to about 10% (w/w), or from about 0.5% (w/w) to about 5% (w/w), orfrom about 0.75% (w/w) to about 1.5% (w/w), by weight of thepolymerizable composition.

In one example of a polymerizable composition, the composition comprisesa first monomer having a first reactivity ratio, and a second monomerhaving a second reactivity ratio that is less than the first reactivityratio. As understood by persons or ordinary skill in the art, areactivity ratio can be defined as the ratio of the reaction rateconstant of each propagating species adding its own monomer to the rateconstant for its addition of other monomer.

For example, the at least one silicon-containing monomer of thepolymerizable composition can comprise, consist essentially of, orconsist of a silicon-containing monomer having a first reactivity ratio,and the b) at least one hydrophilic monomer can comprise a hydrophilicmonomer having a second reactivity ration, and the second reactivityratio is less than the first reactivity ratio. The second reactivityratio can be at least 5% less, or at least 10% less than the firstreactivity ratio.

Such compositions may also include at least one cross-linking agenthaving a reactivity ratio similar to the first reactivity ratio or tothe second ratio. Such compositions may also include at least twocrosslinking agents, the first crosslinking agent having a reactivityratio similar to the first reactivity ratio, and the second crosslinkingagent having a reactivity ratio similar to the second reactivity ratio.In certain examples, the lens precursor compositions may include one ormore removable additives. For example, the polymerizable compositionsmay include one or more compatibilizers, demolding aids, delensing aids,wettability enhancers, and ionoflux reducers which are removable.

By providing relatively slow reacting monomers in the polymerizablecompositions, such as by providing two or more monomer types withdifferent reactivity ratios in the same polymerizable composition, it ispossible to control the rate at which the hydrophilic and hydrophobic(e.g., silicone) monomers react during the curing process, and therebycontrol the wettability of the resulting polymerized lens body. In oneexample, the first slower reacting monomer or crosslinker can comprise avinyl monomer or crosslinker (in other words, a monomer or crosslinkercontaining a vinyl functional group), and the second faster reactingmonomer or crosslinker can comprise a methacrylate monomer orcrosslinker (in other words, a monomer or crosslinker containing amethacrylate functional group).

The use of slower reacting hydrophilic monomers (as opposed to fasterreacting hydrophobic monomers) can result in residual unreactedhydrophilic monomer and partially reacted monomer (includingun-crosslinked or partially crosslinked hydrophilic polymer chains)remaining present in the lens body once the curing process has finished.The presence of these unreacted and partially reacted hydrophilicmonomers such as monomers in the polymerizable composition which do notfully crosslink into the network during the curing process, can providewettability to the polymerized lens body. The non-fully crosslinkedagents, such as unreacted or only partially reacted monomers, oligomers,linear polymers, slightly crosslinked components, and the like, can beextracted from the polymerized component of the polymerized siliconehydrogel contact lens products, or can remain present in the polymerizedlens body following washing.

Additional Hydrogel Components. The polymerizable compositions used inthe lenses and in the methods described herein can also includeadditional components, e.g., one or more initiators, such as one or morethermal initiators, one or more ultraviolet (UV) initiators, visiblelight initiators, combinations thereof, and the like, one or more UVabsorber agents or compounds, or UV radiation or energy absorber,tinting agent, pigments, release agents, antimicrobial compounds, and/orother additives. The term “additive” in the context of the presentdisclosure refers to a compound or any chemical agent provided in thepresent hydrogel contact lens polymerizable compositions or thepolymerized hydrogel contact lens products, but which is not necessaryfor the manufacture of a hydrogel contact lens.

The polymerizable compositions may comprise one or more initiatorcompounds, i.e., a compound capable of initiating polymerization of apolymerizable composition. Thermal initiators, i.e., initiators having a“kick-off” temperature, can be used. For instance, exemplary thermalinitiators that can be employed in the present polymerizablecompositions include 2,2′-azobiz(isobutyronitrile) (AIBN, VAZO®−64),2,2′-azobis(2,4-dimethylpentanenitrile) (VAZO®−52),2,2′-Azobis(2-methylbutyronitrile) (VAZO®−67), and1,1′-azobis(cyclohexanecarbonitrile) (VAZO®−88) . For VAZO® thermalinitiators, the grade number (i.e., 64, 52, 67, 88, etc.) is the Celsiustemperature at which the half-life of the initiator in solution is 10hours. All of the VAZO® thermal initiators described herein areavailable from DuPont (Wilmington, Del., USA). Additional thermalinitiators, including nitrites as well as other types of initiators, areavailable from Sigma Aldrich. Ophthalmically compatible siliconehydrogel contact lenses can be obtained from polymerizable compositionsthat comprise from about 0.05% (w/w) to about 0.8% (w/w), or from about0.1% (w/w) to about 0.6% (w/w), of VAZO®−64 or other thermal initiator.

A UV absorber may be, e.g., a strong UV absorber that exhibitsrelatively high absorption values in the UV-A range of about 320-380nanometers, but is relatively transparent above about 380 nm. Examplesinclude photopolymerizable hydroxybenzophenones and photopolymerizablebenzotriazoles, such as 2-hydroxy-4-acryloyloxyethoxy benzophenone,commercially available as CYASORB UV416 from Cytec Industries, WestPaterson, NJ, USA, 2-hydroxy-4-(2hydroxy-3-methacrylyloxy)propoxybenzophenone, and photopolymerizablebenzotriazoles, commercially available as NORBLOC® 7966 from Noramco,Athens, Ga., USA. Other photopolymerizable UV absorbers suitable for usein accordance with the present disclosure include polymerizable,ethylenically unsaturated triazines, salicylates, aryl-substitutedacrylates, and mixtures thereof. Generally speaking, a UV absorber, ifpresent, is provided in an amount corresponding to about 0.5 weightpercent of the polymerizable composition to about 1.5 weight percent ofthe composition. For example, compositions can include from about 0.6%(w/w) to about 1.0% (w/w) of one or more UV absorbers.

The polymerizable compositions useful in accordance with the presentdisclosure may also include a tinting agent, although both tinted andclear lens products are contemplated. In one example, the tinting agentis a reactive dye or pigment effective to provide color to the resultinglens product. Tinting agents can include, for example, VAT Blue 6(7,16-Dichloro-6,15-dihydroanthrazine-5,9,14,18-tetrone), 1 -Amino-4-[3-(beta-sulfatoethylsufonyeanilio]-2-anthraquinonesulfonic acid (C. I.Reactive Blue 19, RB-19), a copolymer of Reactive Blue 19 andhydroxyethylmethacrylate (RB-19 HEMA)1,4-bis[44(2-methacryl-oxyethyl)phenylamino]anthraquinone (Reactive Blue246, RB-246, available from Arran Chemical Company, Athlone, Ireland),1,4-Bis[(2-hydroxyethyl)amino]−9,10-anthracenedionebis(2-propenoic)ester (RB-247), Reactive Blue 4, RB-4, or a copolymer ofReactive Blue 4 and hydroxyethyl methacrylate (RB-4 HEMA or “BlueHEMA”). Other exemplary tinting agents are disclosed for example, inU.S. Patent Application Publication No. 2008/0048350, the disclosure ofwhich is incorporated in its entirety herein by reference. Othersuitable tinting agents for use in accordance with the presentdisclosure are phthalocyanine pigments such as phthalocyanine blue andphthalocyanine green, chromic-alumina-cobaltous oxide, chromium oxides,and various iron oxides for red, yellow, brown and black colors.Opaquing agents such as titanium dioxide may also be incorporated. Forcertain applications, a mixture of colors may be employed. If employed,tinting agents can be present in an amount ranging from about 0.1% (w/w)to about 15% (w/w), or about 1% (w/w) to about 10% (w/w), or about 4%(w/w) to about 8% (w/w).

The polymerizable compositions may also comprise a demolding aid, thatis to say, one or more ingredients effective in making more facileremoval of the cured contact lenses from their molds. Exemplarydemolding aids include hydrophilic silicones, polyalkylene oxides, andcombinations thereof. The polymerizable compositions may additionallycomprise a diluent selected from the group consisting of hexanol,ethoxyethanol, isopropanol (IPA), propanol, decanol and combinationsthereof. Diluents, if employed, are typically present in amounts rangingfrom about 10% (w/w) to about 30% (w/w). Compositions having relativelyhigher concentrations of diluents tend to, but do not necessarily, havelower ionoflux values, reduced modulus, and increased elongation, aswell as water break up times (WBUTs) greater than or equal to 20seconds. Additional materials suitable for use in making hydrogelcontact lenses are described in U.S. Pat. No. 6,867,245, the disclosureof which is incorporated in its entirety herein by reference. In certainexamples, however, the polymerizable composition is diluent-free.

Silicone-containing hydrogel contact lenses are frequently referred toas silicone hydrogel contact lenses. Many silicone hydrogel contactlenses are based on polymerizable lens formulations that includesiloxane monomers, and at least one hydrophilic monomer, as previouslydescribed. Some examples of silicone hydrogel contact lens materialsinclude materials having the following USANs: acquafilcon A oraquafilcon B, balafilcon A, comfilcon A, enfilcon A, galyfilcon A,lenefilcon A, lotrafilcon A, lotrafilcon B, senofilcon A, narafilcon A,and filcon II 3. In one example, the lens body with ophthalmicallyacceptably wettable anterior and posterior surfaces without applicationof a surface treatment to the lens body, or without the presence of aninterpenetrating polymeric network (IPN) of a polymeric wetting agent inthe lens body is a comfilcon A silicone hydrogel contact lens body.

A method of manufacturing ophthalmic lenses, for example, siliconehydrogel contact lenses, is illustrated in FIG. 1. In accordance withthe present disclosure, all of the steps illustrated in FIG. 1, or witha subset of the steps illustrated in FIG. 1. Items which serve asinputs, outputs or both inputs and outputs of the steps of FIG. 1 areillustrated in FIG. 2. FIG. 1 includes a step 102 of placing apolymerizable composition on or in a mold member, the mold membercomprising a polar thermoplastic polymer with an percent polarity offrom about 1% to about 7% (i.e., a thermoplastic polymer as describedherein). In reference to the present disclosure, the polymerizablecomposition can be understood to be a lens precursor composition, suchas, for example, a polymerizable silicone hydrogel contact lensprecursor composition. The polymerizable composition is illustrated inFIG. 2 as element 202. The polymerizable composition may be understoodto be a pre-polymerized or pre-cured composition suitable forpolymerization. As used herein, the present polymerizable compositionmay also be referred to as a monomer mix.

Typically, the polymerizable composition or lens precursor compositionis not polymerized before curing or polymerization of the composition.However, polymerizable compositions or lens precursor compositions maybe partially polymerized before undergoing a curing process. In oneexample, the polymerizable composition may comprise a polymer componentwhich becomes crosslinked with other components of the polymerizablecomposition during the curing process. The polymeric component can be apolymeric component which is not a polymeric wetting or comfort agent,which does not form an interpenetrating polymeric network in the lensbody, or which is neither a polymeric wetting or comfort agent and doesnot form an IPN in the lens body.

The present lens precursor compositions can be provided in containers,dispensing devices, or contact lens molds prior to a curing orpolymerization procedure, as described herein. Referring back to FIG. 1,in step 102, the lens precursor composition is placed on a lens formingsurface (i.e., a region used to mold a lens surface) of a female contactlens mold member (i.e., within a concave lens forming surface). Thefemale contact lens mold member may be understood to be a first contactlens mold member or an anterior contact lens mold member. For example,the female contact lens mold member has a lens forming surface thatdefines the anterior or front surface of a contact lens produced fromthe contact lens mold. The second contact lens mold member may beunderstood to be a male contact lens mold member or a posterior contactlens mold member. For example, the second contact lens mold memberincludes a lens forming surface that defines the posterior surface of acontact lens produced in the contact lens mold (i.e, the second or malemold member has a convex lens forming surface).

Further in reference to the present disclosure, the first and secondmold members comprise, include, include a major amount of, consistessentially of, or consist of a thermoplastic polymer as describedherein, such as, for example, PBT or acetal, and have been produced, inaccordance with the present disclosure, to have lens forming surfaceswith sufficient degrees of polarity to produce silicone hydrogel contactlenses having ophthalmically acceptably wettable surfaces.

The first contact lens mold member is placed in contact with a secondcontact lens mold member to form a contact lens mold assembly having acontact lens-shaped cavity. The method illustrated in FIG. 1 includes astep 104 of closing a contact lens mold assembly by placing two contactlens mold members in contact with each other to form a contact lens moldassembly with a contact lens-shaped cavity. For example, with referenceto FIG. 2, the polymerizable silicone hydrogel lens precursorcomposition 202 is located in the contact lens shaped cavity.

At step 106, the method illustrated in FIG. 1 includes curing thepolymerizable composition to form a polymerized lens body which has notbeen contacted by a liquid and which is contained in a mold assembly, asillustrated in FIG. 2 as element 204. In one example the polymerizedlens body is a silicone hydrogel contact lens body which has not beencontacted by a liquid. During curing, the components of thepolymerizable composition polymerize to form a polymerized lens body.Thus, the curing may also be understood to be a polymerizing step. Thecuring 106 can include exposing the polymerizable lens precursorcomposition to a form of electromagnetic radiation effective inpolymerizing the components of the lens precursor composition. Forexample, the curing 106 can include exposing the polymerizablecomposition to polymerizing amounts of heat or ultraviolet (UV) light,among other forms of electromagnetic radiation. The curing 106 can alsoinclude curing the compositions in an oxygen-free or nearly oxygen-freeenvironment. For example, the curing 106 can occur in the presence ofnitrogen or other inert gases. The curing 106 can be effective to fullypolymerize the polymerizable composition, or can polymerize thepolymerizable composition to a level such that the lens body whenprocessed (e.g., demolded, delensed, washed, packaged, sterilized, etc.)is capable of retaining its molded shape adequately to serve as acontact lens.

The polymerized lens body which has not been exposed to a liquid refersto a polymerized product prior to undergoing an optional washing processand prior to being contacted by a liquid as part of a wet demolding or awet delensing process. For example, the washing process can be acleaning process to remove dust or debris, an extraction process toremove a portion or substantially all of one or more extractablecomponents' from the polymerized lens body, or a hydration process topartially or fully hydrate the hydrogel lens body. For example, apolymerized lens product which has not been contacted by a liquid may beprovided in a lens shaped cavity of a mold assembly after a curingprocess, may be provided on or in one contact lens mold member after drydemolding of the contact lens mold, or may be provided on or in anextraction tray or other device after a dry delensing procedure andprior to a washing procedure. In one example, a delensed polymerizedlens body which has not been contacted by a liquid can be provided on orin an extraction tray or other device prior to being contacted by aliquid such as, for example, a cleaning liquid, an extraction liquid, ahydration liquid, and combinations thereof.

The polymerized lens body which has not been exposed to a liquid 204 mayinclude a lens forming component, such as a silicon-containing polymericnetwork or matrix in the shape of a lens, and a removable component thatcan be removed from the lens body following polymerization. Theremovable component can be understood to include unreacted monomers,oligomers, partially reacted monomers, or other agents which have notbecome covalently attached or otherwise immobilized relative to thelens-forming component. The removable component can also be understoodto include one or more additives, including diluents, that can beremoved from the polymerized lens product during a cleaning, extraction,or hydration procedure, as discussed herein. Thus, materials of theremovable component can include linear uncross-linked or slightlycross-linked or branched polymers of extractable materials that are notcross-linked to or otherwise immobilized relative to the polymerbackbone, network, or matrix of the lens body.

After curing the polymerizable compositions, the method illustrated inFIG. 1 includes a step 108 of demolding the mold assembly. Demoldingrefers to the process of separating two mold members, such as male andfemale mold members, of a mold assembly containing a polymerized lensbody. The demolding process results in a polymerized lens body remainingin contact with one, and only one, mold member 206 of the two moldmembers used to form the lens body. Following the demolding process, thepolymerized lens body is located on, or remains in contact with just oneof the mold members of the mold assembly. For example, the polymerizedlens body may be located on, or in contact with, the male mold member ormay be located on, or in contact with, the female mold member. When adry demolding process is used, the resulting polymerized lens bodyremaining in contact with one mold member 206 has not been contacted bya liquid.

During a delensing step, a polymerized lens body remaining in contactwith one mold member 206 is released from the one mold member with whichit was in contact, as shown in step 110 of FIG. 1. The lens body can bedelensed from the male mold member or the female mold member, dependingon which mold member the polymerized lens body remained in contact withfollowing the demolding step 108. Following the delensing step, thereleased lens body is a delensed lens body 208. When a dry demoldingprocess is followed by a dry delensing process, the resulting delensedpolymerized lens body is a delensed polymerized lens body which has notbeen contacted by a liquid.

The method illustrated in FIG. 1 optionally includes a step 112 ofwashing the lens body by contacting the polymerized lens body with aliquid, for example an organic solvent, an organic solvent solution,water or an aqueous solution, to clean dust or debris from the lensbody, to extract the lens body to remove extractable materials from thelens body, or to fully or partially hydrate the lens body. The washingstep 112 results in a cleaned, extracted or hydrated lens body 210, asshown in FIG. 2. The washing step 112 can optionally be conducted on amold assembly including a polymerized lens body, a polymerized lens bodyremaining in contact with one mold member 206, a delensed lens body 208,and can be conducted repeatedly during the manufacturing process.

After optionally washing the polymerized lens body, the method canoptionally include a step 114 of hydrating the polymerized lens body.The hydrating step 114 can include contacting a polymerized lens body orone or more batches of such lens bodies with water or an aqueoussolution to form a hydrated lens product, such as, for example, asilicone hydrogel contact lens 212, as shown in FIG. 2. The hydrationstep can fully or partially hydrate the lens body. In one example, thepolymerized lens body which is hydrated in step 114 is a delensedpolymerized lens body which has not been contacted by a liquid prior tothe hydration step 114. In another example, the polymerized lens bodywhich is hydrated in step 114 is a polymerized lens body remaining incontact with one mold member 206 which has not been contacted by aliquid prior to the hydration step 114. In this example, the hydrationstep 114 can act as both a hydration step 114 and a delensing step 110.In yet another example, the polymerized lens body which is hydrated instep 114 can be a polymerized lens body in a mold assembly 204. In thisexample, the polymerized lens body which is hydrated in step 114 is apolymerized lens body contained in a mold assembly which has notpreviously been contacted by a liquid, and the hydration step 114 canserves as both a demolding step 108 and as part or all of a hydrationstep 114.

After demolding, and optionally washing and/or hydrating the polymerizedlens body, the method illustrated in FIG. 1 can optionally include astep 116 of packaging the lens body to produce a packaged ophthalmiclens product 214. For example, the lens body can be placed in a blisterpack, vial or other suitable container along with a volume of apackaging liquid, such as a saline solution, including buffered salinesolutions. In one example, the hydration step 114 and packaging step maybe conducted simultaneously by placing a polymerized lens body which hasnot previously been contacted by a liquid in a blister pack or containerwith a portion of packaging liquid which serves as both a packagingliquid and a hydration solution. The polymerized lens body which ishydrated and packaged simultaneously in this example can be a delensedpolymerized lens body which had not previously been contacted by aliquid, or a polymerized lens body remaining in contact with one moldmember which had not previously been contacted by a liquid, where boththe lens body and the one mold member are placed in the package.

The blister pack or container of the packaged ophthalmic lens product214 can be sealed, and subsequently sterilized, as shown in optionalstep 118 of FIG. 1. For example, the packaged ophthalmic lens productcan be exposed to sterilizing amounts of radiation, including heat, suchas by autoclaving, gamma radiation, e-beam radiation, ultravioletradiation, and the like. Depending upon the previous process steps used,the sterilization process can also serve to partially or fully extract,fully hydrate, or both extract and hydrate the packaged ophthalmic lensbody.

The present invention includes the followingaspects/embodiments/features in any order and/or in any combination:

1. The present invention relates to a method of manufacturing a siliconehydrogel contact lens body, comprising:

providing a first mold member and a second mold member, the first moldmember comprising a concave molding surface configured to mold ananterior surface of a contact lens and the second mold member comprisinga convex molding surface configured to mold a posterior surface of acontact lens, the first mold member and the second mold member beingconfigured to form a lens-shaped cavity therebetween when combined as amold assembly, the molding surface of at least one of the first moldmember and the second mold member comprising a thermoplastic polymer,the molding surface having a percent polarity from 3% to 20% and asurface energy from about 25 mN/m to about 40 mN/m;

placing a polymerizable composition comprising a) at least onesilicon-containing monomer and b) at least one hydrophilic monomer inthe first mold member, the polymerizable composition having a surfacetension from about 20 mN/m to about 25 mN/m, and a surface energydifferential of the surface tension of the polymerizable compositionless the surface energy of the molding surface is less than or equal tozero (0);

assembling the mold assembly by placing the second mold member incontact with the first mold member so as to form a lens-shaped cavitytherebetween with the polymerizable composition contained in thelens-shaped cavity of the mold assembly; and curing the polymerizablecomposition in the mold assembly to form a cast-molded polymerizedreaction product in the lens-shaped cavity of the mold assembly, thepolymerized reaction product comprising a silicone hydrogel contact lensbody.

2. The method of any preceding or following embodiment/feature/aspect,wherein the molding surface of the at least one of the first mold memberand the second mold member comprises a mixture of a thermoplasticpolymer and an additive.

3. The method of any preceding or following embodiment/feature/aspect,wherein the molding surface formed of the mixture of the thermoplasticpolymer and the additive has a percent polarity at least 1% higher and asurface energy at least 1 mN/m lower than a molding surface formed underthe same conditions but of the thermoplastic polymer alone.

4. The method of any preceding or following embodiment/feature/aspect,wherein the additive comprises a non-ionic surfactant, a fatty acidamide, or a form of silicone oil, or any combination thereof.

5. The method of any preceding or following embodiment/feature/aspect,wherein the additive comprises a fatty acid amide.

6. The method of any preceding or following embodiment/feature/aspect,wherein the additive comprises a non-ionic surfactant.

7. The method of any preceding or following embodiment/feature/aspect,wherein the non-ionic surfactant is a non-ionic surfactant having astructure including a linear hydrocarbon portion at least 8 carbons inlength.

8. The method of any preceding or following embodiment/feature/aspect,wherein the thermoplastic polymer comprises a form of polypropylene.

9. The method of any preceding or following embodiment/feature/aspect,wherein the thermoplastic polymer comprises a cyclic olefin polymer.

10. The method of any preceding or following embodiment/feature/aspect,wherein the thermoplastic polymer comprises polybutylene terephthalate(PBT), the at least one of the first mold member and the second moldmember comprising the thermoplastic polymer molding surface is formed byinjection molding, and the mold tool used to form the mold member ismaintained at a temperature from about 30° C. to about 70° C. during theinjection molding.

11. The method of any preceding or following embodiment/feature/aspect,wherein the percent polarity of the molding surface is from about 3% toabout 17%.

12. The method of any preceding or following embodiment/feature/aspect,wherein a percent polarity of the polymerizable composition is fromabout 2% to about 10%.

13. The method of any preceding or following embodiment/feature/aspect,wherein a polarity differential of a percent polarity of thepolymerizable composition less a percent polarity of the molding surfaceis from about +6 to about −6.

14. The method of any preceding or following embodiment/feature/aspect,wherein the polymerizable composition and the molding surface of atleast one of the first mold member and the second mold member have aspreading coefficient greater than or equal to about 10 mN/m.

15. The method of any preceding or following embodiment/feature/aspect,wherein the lens body has ophthalmically acceptably wettable anteriorand posterior surfaces without application of a surface treatment to thelens body, or without the presence of an interpenetrating network (IPN)of a polymeric wetting agent in the lens body.

16. The method of any preceding or following embodiment/feature/aspect,wherein method further comprises the steps of separating the moldassembly using a dry demolding method which does not involve applicationof a liquid to the mold assembly comprising the lens body, and ofdelensing the lens body using a dry delensing method which does notinvolve application of a liquid to the lens body.

17. The method of any preceding or following embodiment/feature/aspect,wherein the hydrophilic monomer of the polymerizable compositioncomprises a hydrophilic monomer with an N-vinyl group.

18. The method of any preceding or following embodiment/feature/aspect,wherein the a) at least one silicon-containing monomer comprises asilicon-containing monomer having a first reactivity ratio, and the b)at least one hydrophilic monomer comprises a hydrophilic monomer havinga second reactivity ration, and the second reactivity ratio is less thanthe first reactivity ratio.

19. The method of any preceding or following embodiment/feature/aspect,wherein the average adhesion energy between the molding surface and thepolymerized lens body is from about 45 mJ/m² to about 60 mJ/m².

20. A silicone hydrogel contact lens body, comprising: a cast-moldedpolymerized lens body comprising the reaction product of a polymerizablecomposition, the polymerizable composition comprising a) at least onesilicon-containing monomer, and b) at least one hydrophilic monomer, thepolymerizable composition having a surface tension from about 20 mN/m toabout 25 mN/m; wherein the lens body is cast-molded in a mold assemblycomprising a first mold member and a second mold member, at least one ofthe first mold member and the second mold member having a thermoplasticpolymer molding surface, the molding surface having a polarity from 3%to 20% and a surface energy from about 25 mN/m to about 40 mN/m, whereina surface energy differential between the surface tension of thepolymerizable composition and the surface energy of the molding surfaceis less than or equal to zero (0); and the lens body has ophthalmicallyacceptably wettable anterior and posterior surfaces without applicationof a surface treatment to the lens body, or without the presence of aninterpenetrating network (IPN) of a polymeric wetting agent in the lensbody.

21. The present invention also relates to a method of manufacturing asilicone hydrogel contact lens body, comprising:

providing a first mold member and a second mold member, the first moldmember comprising a concave molding surface configured to mold ananterior surface of a contact lens and the second mold member comprisinga convex molding surface configured to mold a posterior surface of acontact lens, the first mold member and the second mold member beingconfigured to form a lens-shaped cavity therebetween when combined as amold assembly, the molding surface of at least one of the first moldmember and the second mold member comprising a thermoplastic polymer,the molding surface having a percent polarity from 3% to 30%, and havinga surface energy from about 25 mN/m to about 40 mN/m;

placing a polymerizable composition comprising a) at least onesilicon-containing monomer and b) at least one hydrophilic monomer inthe first mold member, the polymerizable composition having a surfacetension from about 20 mN/m to about 25 mN/m, and a surface energydifferential of the surface tension of the polymerizable compositionless the surface energy of the molding surface is less than or equal tozero (0);

assembling the mold assembly by placing the second mold member incontact with the first mold member so as to form a lens-shaped cavitytherebetween with the polymerizable composition contained in thelens-shaped cavity of the mold assembly; and

curing the polymerizable composition in the mold assembly to form acast-molded polymerized reaction product in the lens-shaped cavity ofthe mold assembly, the polymerized reaction product comprising asilicone hydrogel contact lens body.

22. A silicone hydrogel contact lens body, comprising:

a cast-molded polymerized lens body comprising the reaction product of apolymerizable composition, the polymerizable composition comprising a)at least one silicon-containing monomer, and b) at least one hydrophilicmonomer, the polymerizable composition having a surface tension fromabout 20 mN/m to about 25 mN/m; wherein the lens body is cast-molded ina mold assembly comprising a first mold member and a second mold member,at least one of the first mold member and the second mold member havinga thermoplastic polymer molding surface, the molding surface having apercent polarity from 3% to 20% and having a surface energy from about25 mN/m to about 40 mN/m, wherein a surface energy differential betweenthe surface tension of the polymerizable composition and the surfaceenergy of the molding surface is less than or equal to zero (0); and thelens body has ophthalmically acceptably wettable anterior and posteriorsurfaces without application of a surface treatment to the lens body, orwithout the presence of an interpenetrating network (IPN) of a polymericwetting agent in the lens body.

23. The method or the lens body of any preceding or followingembodiment/feature/aspect, wherein the molding surface of the at leastone of the first mold member and the second mold member comprises amixture of a thermoplastic polymer and an additive.

24. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the molding surface formed of themixture of the thermoplastic polymer and the additive has a percentpolarity at least 1% higher and a surface energy at least lmN/m lowerthan a molding surface formed under the same conditions but of thethermoplastic polymer alone.

25. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the additive comprises a non-ionicsurfactant, a fatty acid amide, or a form of silicone oil, or anycombination thereof.

26. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the additive comprises a fatty acidamide.

27. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the additive comprises a non-ionicsurfactant.

28. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the non-ionic surfactant is anon-ionic surfactant having a structure including a linear hydrocarbonportion at least 8 carbons in length.

29. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the thermoplastic polymer comprises aform of polypropylene.

30. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the thermoplastic polymer comprises acyclic olefin homopolymer or copolymer.

31. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the thermoplastic polymer comprisespolybutylene terephthalate (PBT), the at least one of the first moldmember and the second mold member comprising the thermoplastic polymermolding surface is formed by injection molding, and the mold tool usedto form the at least one mold member is maintained at a temperature fromabout 30° C. to about 70° C. during the injection molding.

32. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein a percent polarity of the moldingsurface is from about 3% to about 17%.

33. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein a percent polarity of the moldingsurface of the first mold member and an percent polarity of the moldingsurface of the second mold member are approximately the same.

34. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the polarity of the polymerizablecomposition is from about 2% to about 10%.

35. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein a polarity differential of a polarityof the polymerizable composition less a polarity of the molding surfaceis from about +6 to about −6.

36. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the polymerizable composition and themolding surface of at least one of the first mold member and the secondmold member have a spreading coefficient greater than or equal to about10 mN/m.

37. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the lens body has ophthalmicallyacceptably wettable anterior and posterior surfaces without applicationof a surface treatment to the lens body, or without the presence of aninterpenetrating network (IPN) of a polymeric wetting agent in the lensbody.

38. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein method further comprises the steps ofseparating the mold assembly using a dry demolding method which does notinvolve application of a liquid to the mold assembly comprising the lensbody, and of delensing the lens body using a dry delensing method whichdoes not involve application of a liquid to the lens body.

39. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the hydrophilic monomer of thepolymerizable composition comprises a hydrophilic monomer with anN-vinyl group.

40. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the a) at least onesilicon-containing monomer comprises a silicon-containing monomer havinga first reactivity ratio, and the b) at least one hydrophilic monomercomprises a hydrophilic monomer having a second reactivity ration, andthe second reactivity ratio is less than the first reactivity ratio.

41. The method or lens body of any preceding or followingembodiment/feature/aspect, wherein the average adhesion energy betweenthe molding surface and the polymerized lens body is from about 45 mJ/m2to about 60 mJ/m2.

The present invention can include any combination of these variousfeatures or embodiments above and/or below as set forth in sentencesand/or paragraphs. Any combination of disclosed features herein isconsidered part of the present invention and no limitation is intendedwith respect to combinable features.

The following non-limiting Examples illustrate certain aspects of thepresent methods and devices.

Example 1

A quantity of polypropylene admixed with 5% CRODAMIDE OR™ fatty acidamide is provided in granular or pellet form. A portion of the polymermixture is processed by conventional injection molding into contact lensmold members. The molding surface of the mold members have a totalsurface energy of about 25 mN/m, and a percent polarity of about 9%.When the polypropylene without the CRODAMIDE OR™ is used to preparecomparative molding surfaces, the molding surfaces have a total surfaceenergy of about 28 mN/m, and a percent polarity of 0%. A polymerizablecomposition having a total surface tension of about 23 mN/m forproducing silicone hydrogel contact lenses comprising VMA is prepared,and is used to prepare a plurality of cast-molded polymerized siliconehydrogel lens bodies as illustrated in FIG. 1. The surface energydifferential of the polymerizable composition and the molding surface isabout −2 mN/m. After UV or thermal curing, the mold assemblies includingthe cast-molded polymerized lens bodies are dry demolded to separate thetwo mold members of the mold assembly. The mold assemblies are readilydry demolded to obtain a mold member with a polymerized lens body ofacceptable quality for use as a contact lens remaining in contact withthe one mold member. The yield of demolded mold members in contact withlens bodies of acceptable quality is greater than or equal to about 75%.Following the dry demolding step, a wet delensing process is used torelease the polymerized lens bodies from the one mold member with whichthey remain in contact following the demolding step. The yield ofcosmetically acceptable dry delensed lenses is greater than or equal toabout 75% of yield of demolded lenses. The released lens bodiessubsequently either are washed using a liquid comprising an organicsolvent followed by an aqueous solution essentially free of an organicsolvent, or are washed using an aqueous solution essentially free of anorganic solvent. The washing step can include an additional hydrationstep, or a separate hydration step can be included before the lensbodies are packaged and sterilized. The lens bodies are not treatedusing a surface treatment to increase wettability, and do not contain aninterpenetrating network of a polymeric wetting agent. Once the lensbodies are fully hydrated, they have ophthalmically acceptably wettablesurfaces.

Example 2

A quantity of polypropylene admixed with 3% SPAN 80™ non-ionicsurfactant (Croda International Plc, Goole, East Yorkshire, UK) isprovided in granular or pellet form. A portion of the polymer mixture isprocessed by conventional injection molding into contact lens moldmembers. The molding surface of the mold members have a total surfaceenergy of about 27 mN/m, and a percent polarity of about 11%. When thepolypropylene without the SPAN 80™ is used to prepare comparativemolding surfaces, the molding surfaces have a total surface energy ofabout 28 mN/m, and a percent polarity of 0%. A polymerizable compositionhaving a total surface tension of about 23 mN/m for producing siliconehydrogel contact lenses comprising VMA is prepared, and is used toprepare a plurality of cast-molded polymerized silicone hydrogel lensbodies as illustrated in FIG. 1. The surface energy differential of thepolymerizable composition and the molding surface is about −4 mN/m.After UV or thermal curing, the mold assemblies including thecast-molded polymerized lens bodies are dry demolded to separate the twomold members of the mold assembly. The mold assemblies are readily drydemolded to obtain a mold member with a polymerized lens body ofacceptable quality for use as a contact lens remaining in contact withthe one mold member. The yield of demolded mold members in contact withlens bodies of acceptable quality is greater than or equal to about 75%.Following the dry demolding step, a wet delensing process is used torelease the polymerized lens bodies from the one mold member with whichthey remain in contact following the demolding step. The yield ofcosmetically acceptable dry delensed lenses is greater than or equal toabout 75% of yield of demolded lenses. The released lens bodiessubsequently either are washed using a liquid comprising an organicsolvent followed by an aqueous solution essentially free of an organicsolvent, or are washed using an aqueous solution essentially free of anorganic solvent. The washing step can include an additional hydrationstep, or a separate hydration step can be included before the lensbodies are packaged and sterilized. The lens bodies are not treatedusing a surface treatment to increase wettability, and do not contain aninterpenetrating network of a polymeric wetting agent. Once the lensbodies are fully hydrated, they have ophthalmically acceptably wettablesurfaces.

Example 3

A quantity of polypropylene admixed with 3% TWEEN 80™ non-ionicsurfactant (ICI Americas, Wilmington, Del., USA) is provided in granularor pellet form. A portion of the polymer mixture is processed byconventional injection molding into contact lens mold members. Themolding surface of the mold members have a total surface energy of about24 mN/m, and a percent polarity of about 14%. When the polypropylenewithout the TWEEN 80™is used to prepare comparative molding surfaces,the molding surfaces have a total surface energy of about 28 mN/m, and apercent polarity of 0%. A polymerizable composition having a totalsurface tension of about 23 mN/m for producing silicone hydrogel contactlenses comprising VMA is prepared, and is used to prepare a plurality ofcast-molded polymerized silicone hydrogel lens bodies as illustrated inFIG. 1. The surface energy differential of the polymerizable compositionand the molding surface is about −1 mN/m. After UV or thermal curing,the mold assemblies including the cast-molded polymerized lens bodiesare dry demolded to separate the two mold members of the mold assembly.The mold assemblies are readily dry demolded to obtain a mold memberwith a polymerized lens body of acceptable quality for use as a contactlens remaining in contact with the one mold member. The yield ofdemolded mold members in contact with lens bodies of acceptable qualityis greater than or equal to about 75%. Following the dry demolding step,a wet delensing process is used to release the polymerized lens bodiesfrom the one mold member with which they remain in contact following thedemolding step. The yield of cosmetically acceptable dry delensed lensesis greater than or equal to about 75% of yield of demolded lenses. Thereleased lens bodies subsequently either are washed using a liquidcomprising an organic solvent followed by an aqueous solutionessentially free of an organic solvent, or are washed using an aqueoussolution essentially free of an organic solvent. The washing step caninclude an additional hydration step, or a separate hydration step canbe included before the lens bodies are packaged and sterilized. The lensbodies are not treated using a surface treatment to increasewettability, and do not contain an interpenetrating network of apolymeric wetting agent. Once the lens bodies are fully hydrated, theyhave ophthalmically acceptably wettable surfaces.

Example 4

A quantity of ZEONOR™ 1420R admixed with an additive is provided ingranular or pellet form. A portion of the polymer mixture is processedby conventional injection molding into contact lens mold members. Themolding surface of the mold members have a total surface energy of about33 mN/m, and a percent polarity of about 14%. When the ZEONOR™ 1420Rwithout the additive is used to prepare comparative molding surfaces,the molding surfaces have a total surface energy of about 33 mN/m, and apercent polarity of about 0%. A polymerizable composition having a totalsurface tension of about 23 mN/m for producing silicone hydrogel contactlenses comprising VMA is prepared, and is used to prepare a plurality ofcast-molded polymerized silicone hydrogel lens bodies as illustrated inFIG. 1. The surface energy differential of the polymerizable compositionand the molding surface is about −10 mN/m. After UV or thermal curing,the mold assemblies including the cast-molded polymerized lens bodiesare dry demolded to separate the two mold members of the mold assembly.The mold assemblies are readily dry demolded to obtain a mold memberwith a polymerized lens body of acceptable quality for use as a contactlens remaining in contact with the one mold member. The yield ofdemolded mold members in contact with lens bodies of acceptable qualityis greater than or equal to about 75%. Following the dry demolding step,a wet delensing process is used to release the polymerized lens bodiesfrom the one mold member with which they remain in contact following thedemolding step. The yield of cosmetically acceptable dry delensed lensesis greater than or equal to about 75% of yield of demolded lenses. Thereleased lens bodies subsequently either are washed using a liquidcomprising an organic solvent followed by an aqueous solutionessentially free of an organic solvent, or are washed using an aqueoussolution essentially free of an organic solvent. The washing step caninclude an additional hydration step, or a separate hydration step canbe included before the lens bodies are packaged and sterilized. The lensbodies are not treated using a surface treatment to increasewettability, and do not contain an interpenetrating network of apolymeric wetting agent. Once the lens bodies are fully hydrated, theyhave ophthalmically acceptably wettable surfaces.

While these methods and devices have been described with respect tovarious specific examples, it is to be understood that the disclosure isnot limited thereto and that the methods and devices can be variouslypracticed within the scope of the following claims.

Applicants specifically incorporate the entire contents of all citedreferences in this disclosure. Further, when an amount, concentration,or other value or parameter is given as either a range, preferred range,or a list of upper preferable values and lower preferable values, thisis to be understood as specifically disclosing all ranges formed fromany pair of any upper range limit or preferred value and any lower rangelimit or preferred value, regardless of whether ranges are separatelydisclosed. Where a range of numerical values is recited herein, unlessotherwise stated, the range is intended to include the endpointsthereof, and all integers and fractions within the range. It is notintended that the scope of the invention be limited to the specificvalues recited when defining a range.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the present specification andpractice of the present invention disclosed herein. It is intended thatthe present specification and examples be considered as exemplary onlywith a true scope and spirit of the invention being indicated by thefollowing claims and equivalents thereof.

What is claimed is:
 1. A method of manufacturing a silicone hydrogelcontact lens body, comprising: providing a first mold member and asecond mold member, the first mold member comprising a concave moldingsurface configured to mold an anterior surface of a contact lens and thesecond mold member comprising a convex molding surface configured tomold a posterior surface of a contact lens, the first mold member andthe second mold member being configured to form a lens-shaped cavitytherebetween when combined as a mold assembly, the molding surface of atleast one of the first mold member and the second mold member comprisinga thermoplastic polymer, the molding surface having a percent polarityfrom 3% to 20% and a surface energy from about 25 mN/m to about 40 mN/m;placing a polymerizable composition comprising a) at least onesilicon-containing monomer and b) at least one hydrophilic monomer inthe first mold member, the polymerizable composition having a surfacetension from about 20 mN/m to about 25 mN/m, and a surface energydifferential of the surface tension of the polymerizable compositionless the surface energy of the molding surface is less than or equal tozero (0); assembling the mold assembly by placing the second mold memberin contact with the first mold member so as to form a lens-shaped cavitytherebetween with the polymerizable composition contained in thelens-shaped cavity of the mold assembly; and curing the polymerizablecomposition in the mold assembly to form a cast-molded polymerizedreaction product in the lens-shaped cavity of the mold assembly, thepolymerized reaction product comprising a silicone hydrogel contact lensbody.
 2. The method of claim 1, wherein the molding surface of the atleast one of the first mold member and the second mold member comprisesa mixture of a thermoplastic polymer and an additive.
 3. The method ofclaim 2, wherein the molding surface formed of the mixture of thethermoplastic polymer and the additive has a percent polarity at least1% higher and a surface energy at least lmN/m lower than a moldingsurface formed under the same conditions but of the thermoplasticpolymer alone.
 4. The method of claim 2, wherein the additive comprisesa non-ionic surfactant, a fatty acid amide, or a form of silicone oil,or any combination thereof.
 5. The method of claim 2, wherein theadditive comprises a fatty acid amide.
 6. The method of claim 2, whereinthe additive comprises a non-ionic surfactant.
 7. The method of claim 6,wherein the non-ionic surfactant is a non-ionic surfactant having astructure including a linear hydrocarbon portion at least 8 carbons inlength.
 8. The method of claim 1, wherein the thermoplastic polymercomprises a form of polypropylene.
 9. The method of claim 1, wherein thethermoplastic polymer comprises a cyclic olefin polymer.
 10. The methodof claim 1, wherein the thermoplastic polymer comprises polybutyleneterephthalate (PBT), the at least one of the first mold member and thesecond mold member comprising the thermoplastic polymer molding surfaceis formed by injection molding, and the mold tool used to form the moldmember is maintained at a temperature from about 30° C. to about 70° C.during the injection molding.
 11. The method of claim 1, wherein thepercent polarity of the molding surface is from about 3% to about 17%.12. The method of claim 1, wherein a percent polarity of thepolymerizable composition is from about 2% to about 10%.
 13. The methodof claim 1, wherein a polarity differential of a percent polarity of thepolymerizable composition less a percent polarity of the molding surfaceis from about +6 to about −6.
 14. The method of claim 1, wherein thepolymerizable composition and the molding surface of at least one of thefirst mold member and the second mold member have a spreadingcoefficient greater than or equal to about 10 mN/m.
 15. The method ofclaim 1, wherein the lens body has ophthalmically acceptably wettableanterior and posterior surfaces without application of a surfacetreatment to the lens body, or without the presence of aninterpenetrating network (IPN) of a polymeric wetting agent in the lensbody.
 16. The method of claim 1, wherein method further comprises thesteps of separating the mold assembly using a dry demolding method whichdoes not involve application of a liquid to the mold assembly comprisingthe lens body, and of delensing the lens body using a dry delensingmethod which does not involve application of a liquid to the lens body.17. The method of claim 1, wherein the hydrophilic monomer of thepolymerizable composition comprises a hydrophilic monomer with anN-vinyl group.
 18. The method of claim 1, wherein the a) at least onesilicon-containing monomer comprises a silicon-containing monomer havinga first reactivity ratio, and the b) at least one hydrophilic monomercomprises a hydrophilic monomer having a second reactivity ration, andthe second reactivity ratio is less than the first reactivity ratio. 19.The method of claim 1, wherein the average adhesion energy between themolding surface and the polymerized lens body is from about 45 mJ/m² toabout 60 mJ/m².
 20. A silicone hydrogel contact lens body, comprising: acast-molded polymerized lens body comprising the reaction product of apolymerizable composition, the polymerizable composition comprising a)at least one silicon-containing monomer, and b) at least one hydrophilicmonomer, the polymerizable composition having a surface tension fromabout 20 mN/m to about 25 mN/m; wherein the lens body is cast-molded ina mold assembly comprising a first mold member and a second mold member,at least one of the first mold member and the second mold member havinga thermoplastic polymer molding surface, the molding surface having apolarity from 3% to 20% and a surface energy from about 25 mN/m to about40 mN/m, wherein a surface energy differential between the surfacetension of the polymerizable composition and the surface energy of themolding surface is less than or equal to zero (0); and the lens body hasophthalmically acceptably wettable anterior and posterior surfaceswithout application of a surface treatment to the lens body, or withoutthe presence of an interpenetrating network (IPN) of a polymeric wettingagent in the lens body.